Process for enzymatic hydrolysis of lignocellulosic material and fermentation of sugars

ABSTRACT

The invention relates to a process for the preparation of a sugar and/or fermentation product from lignocellulosic material.

FIELD OF THE INVENTION

The invention relates to a process for the enzymatic hydrolysis oflignocellulosic material and fermentation of sugars.

BACKGROUND OF THE INVENTION

Lignocellulosic material is primarily composed of cellulose,hemicellulose and lignin and provides an attractive platform forgenerating alternative energy sources to fossil fuels. The material isavailable in large amounts and can be converted into valuable productse.g. sugars or biofuel, such as bioethanol.

Producing fermentation products from lignocellulosic material is knownin the art and generally includes the steps of pretreatment, hydrolysis,fermentation, and optionally recovery of the fermentation products.

During the hydrolysis, which may comprise the steps of liquefaction,pre-saccharification and/or saccharification, cellulose present in thelignocellulosic material is partly (typically 30 to 95%, dependable onenzyme activity and hydrolysis conditions) converted into reducingsugars by cellulolytic enzymes. The hydrolysis typically takes placeduring a process lasting 6 to 168 hours (see Kumar, S., Chem. Eng.Technol. 32 (2009), 517-526) under elevated temperatures of 45 to 50° C.and non-sterile conditions.

Commonly, the sugars are then converted into valuable fermentationproducts such as ethanol by microorganisms like yeast. The fermentationtakes place in a separate, preferably anaerobic, process step, either inthe same or in a different vessel. The temperature during fermentationis adjusted to 30 to 33° C. to accommodate growth and ethanol productionby microorganisms, commonly yeasts. During the fermentation process, theremaining cellulosic material is converted into reducing sugars by theenzymes already present from the hydrolysis step, while microbialbiomass and ethanol are produced. The fermentation is finished once thecellulosic material is converted into fermentable sugars and allfermentable sugars are converted into ethanol, carbon dioxide andmicrobial biomass. This may take up to 6 days. In general, the overallprocess time of hydrolysis and fermentation may amount up to 13 days.

In general, cost of enzyme production is a major cost factor in theoverall production process of fermentation products from lignocellulosicmaterial (see Kumar, S., Chem. Eng. Technol. 32 (2009), 517-526). Thusfar, reduction of enzyme production costs is achieved by applying enzymeproducts from a single or from multiple microbial sources (see WO2008/008793) with broader and/or higher (specific) hydrolytic activity.This leads to a lower enzyme need, faster conversion rates and/or ahigher conversion yields, and thus to lower overall production costs.

Next to the optimization of enzymes, optimization of process design is acrucial tool to reduce overall costs of the production of fermentationproducts.

For economic reasons, it is therefore desirable to include new andinnovative process configurations aimed at reducing overall productioncosts in the process involving hydrolysis and fermentation oflignocellulosic material.

SUMMARY OF THE INVENTION

An object of the invention is to provide an improved process for thepreparation of a sugar product and/or a fermentation product fromlignocellulosic material. Another object is to provide a processinvolving hydrolysis, wherein the process conditions of the hydrolysisare optimized. Optimization lies in any of the following features.

The hydrolysis process performed in the present invention comprises atleast two steps, a step wherein the enzymatic hydrolysis is performed ata first temperature and a second step wherein the enzymatic hydrolysisis performed at a second temperature, wherein the second temperature islower than the first temperature. Oxygen is added to the hydrolysisduring at least part of the second step.

Oxygen not only stimulates glucan hydrolysis, it also leads to enzymeinactivation. This inactivation can be limited by application of oxygenat lower temperature. The application of oxygen at low temperature doesnot have a negative effect on the glucan hydrolysis. It is thereforebeneficial to apply oxygen (aeration) at a lower temperature than theoptimal enzyme performance temperature.

A very accurate and careful oxygen addition and control is essential incase oxygen is applied at the optimal enzyme performance temperature(maximal enzyme performance at the lowest possible enzyme inactivation).This is difficult and more expensive compared with oxygen addition atdecreased temperature, since at low temperature there is a limited, oreven absent, enzyme inactivation. Therefore, oxygen addition atdecreased temperature allows for cheap and easy controllable oxygenaddition.

Large scale ethanol production facilities normally contain severallignocellulosic feedstock hydrolysis containers (that often operate inparallel) and also several fermentation containers in which ethanol isproduced. To reduce cost, large scale ethanol production facilitiesgenerally contain only one heat exchanger to cool the biomass afterhydrolysis to a suitable fermentation temperature. If oxygen addition isapplied after the heat exchanger and prior to fermentation, only oneoxygen addition system is needed. This solution is much cheaper thanwhen oxygen is added to each individual hydrolysis container.

Oxygen addition at low temperature (e.g. fermentation temperature) canbe combined with yeast propagation prior to the ethanol fermentationprocess. So, the propagation step wherein yeast is propagated can becombined with the second stage of the processes according to the presentinvention.

Oxygen addition at reduced temperature leads to reduced lignin oxidationand consequently a reduced pH drop. The necessity for pH control mighttherefore be absent.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the present specification and the accompanying claims, thewords “comprise” and “include” and variations such as “comprises”,“comprising”, “includes” and “including” are to be interpretedinclusively. That is, these words are intended to convey the possibleinclusion of other elements or integers not specifically recited, wherethe context allows. The articles “a” and “an” are used herein to referto one or to more than one (i.e. to one or at least one) of thegrammatical object of the article. By way of example, “an element” maymean one element or more than one element.

In case liquefaction and saccharification are combined, the one or morecontainers used in the first stage are called first container(s), theone or more containers used in the second stage are called secondcontainer(s) and the one or more containers used in the fermentation arecalled third container(s). In case liquefaction and saccharification areseparate steps, the one or more containers used for the liquefaction arecalled first container(s), the one or more containers used in thesaccharification are called second container(s), the one or morecontainers used in the second stage are called third container(s) andthe one or more containers used in the fermentation are called fourthcontainer(s).

The container used in the second stage can be a container, but can alsobe a tube or any other continuous system. The second stage may also beperformed in the one or more fermentation containers before thefermentation starts. Oxygen may be introduced through sparging, but mayalso be introduced by filling the one or more containers from the top,allowing the hydrolysate to fall down and consequently introducesufficient oxygen into the hydrolysate. In an embodiment oxygen is addedbefore the fermenting microorganism is added. The second stage may alsobe performed in the one or more containers used for the propagation ofthe fermenting microorganisms (propagation containers). Oxygen may beintroduced through sparging, but may also be introduced by filling theone or more propagation containers from the top, allowing thehydrolysate to fall down and consequently introduce sufficient oxygeninto the hydrolysate.

The present invention relates to a process for the preparation of asugar product from lignocellulosic material, comprising the step ofenzymatic hydrolysis of the lignocellulosic material in one or morecontainers using an enzyme composition comprising at least twocellulases to obtain a sugar product, wherein the enzymatic hydrolysiscomprises at least a first stage wherein the enzymatic hydrolysis isperformed at a first temperature, and a second stage wherein theenzymatic hydrolysis is performed at a second temperature, wherein thesecond temperature is lower than the first temperature and whereinoxygen is added to the hydrolysis during at least part of the secondstage.

The present invention also relates to a process for the preparation of afermentation product from lignocellulosic material, comprising thefollowing steps (a) performing a process for the preparation of a sugarproduct from lignocellulosic material as described above, (b)fermentation of the sugar product to produce a fermentation product, and(c) optionally, recovery of the fermentation product.

In an embodiment the processes of the present invention comprise a firststage wherein the enzymatic hydrolysis is performed at a firsttemperature. Said first temperature is from 50-90° C., preferably from52-80° C., more preferably from 55-75° C. and most preferably from57-65° C.

The first stage of the processes according to the present invention maybe an enzymatic hydrolysis wherein liquefaction and saccharification arecombined. In an embodiment the first stage is anaerobic. Alternatively,the first stage of the processes according to the present invention maybe an enzymatic hydrolysis wherein liquefaction and saccharification areseparate steps. Liquefaction and saccharification may be performed atdifferent temperatures, but may also be performed at a singletemperature, such as the first temperature described above. In anembodiment the temperature of the liquefaction is higher than thetemperature of the saccharification. Liquefaction is preferably carriedout at a temperature of 65-75° C. and saccharification is preferablycarried out at a temperature of 50-65° C.

The present invention also relates to a process for the preparation of asugar product from lignocellulosic material, comprising the step ofenzymatic hydrolysis of the lignocellulosic material in one or morecontainers using an enzyme composition comprising at least twocellulases to obtain a sugar product, wherein the enzymatic hydrolysiscomprises at least (a) a first stage, said first stage comprising aliquefaction step and a saccharification step, wherein the liquefactionstep is performed at a first temperature and the saccharification stepis performed at a second temperature, wherein the second temperature islower than the first temperature, and (b) a second stage wherein theenzymatic hydrolysis is performed at a third temperature, wherein thethird temperature is lower than the second temperature and whereinoxygen is added to the hydrolysis during at least part of the secondstage. In an embodiment the first stage is performed in one or morefirst containers. In an embodiment the second stage is performed in oneor more second containers. When liquefaction and saccharification areseparate steps, the liquefaction step may be performed in one or morefirst containers and the saccharification step may be performed in oneor more second containers and the second stage may be performed in oneor more third containers.

In an embodiment the processes of the present invention comprise asecond stage wherein the enzymatic hydrolysis is performed at a secondtemperature. Said second temperature is from 20-49° C., preferably25-45° C., more preferably 30-40° C. In case of a process whereinliquefaction and saccharification are separate steps, the temperature ofthe second stage is called third temperature. In such cases, theprocesses of the present invention comprise a second stage wherein theenzymatic hydrolysis is performed at a third temperature. Said thirdtemperature is from 20-49° C., preferably 25-45° C., more preferably30-40° C.

In the processes according to the present invention lignocellulosicmaterial may be added to the one or more first containers. In anembodiment the enzyme composition comprising at least two cellulases isalready present in the one or more first containers before thelignocellulosic material is added. In another embodiment the enzymecomposition comprising at least two cellulases may be added to the oneor more first containers. In an embodiment the lignocellulosic materialis already present in the one or more first containers before the enzymecomposition comprising at least two cellulases is added. In anembodiment both the lignocellulosic material and the enzyme compositioncomprising at least two cellulases are added simultaneously to the oneor more first containers. The enzyme composition present in the one ormore first containers may be an aqueous composition.

The lignocellulosic material used in the processes of the presentinvention may be washed and/or pretreated.

In an embodiment additional enzymes are added after the first stage ofthe processes according to the present invention. The additional enzymesmay be added before or during the second stage. In case the first stagecomprises a separate liquefaction step and saccharification step,additional enzymes may be added during and/or after the liquefactionstep. These additional enzymes may be added before and/or during thesaccharification step. Additional enzymes may also be added after thesaccharification step, before and/or during the second stage.

In an embodiment the first stage takes 12-200 hours, preferably 18-120hours, more preferably 24-72 hours. In case of a process whereinliquefaction and saccharification are separate steps, the liquefactionstep takes 2-24 hours, preferably 4-18 hours, more preferably 4-12 hoursand/or the saccharification step takes 10-200 hours, preferably 24-120hours, more preferably 24-72 hours.

In an embodiment the second stage takes 2-72 hours, preferably 4-48hours, and more preferably 8-24 hours.

In an embodiment the total hydrolysis time (i.e. time of first stage andsecond stage) is 14 hours or more, 16 hours or more, 18 hours or more,20 hours or more, 30 hours or more, 40 hours or more, 50 hours or more,60 hours or more, 70 hours or more, 80 hours or more, 90 hours or more,100 hours or more.

In an embodiment, the total hydrolysis time (i.e. time of first stageand second stage) is 14 to 272 hours, 16 to 248 hours, preferably 20 to224 hours. Due to the stability of the enzyme composition longerhydrolysis reaction times are possible with corresponding higher sugaryields.

In case of the processes according to the present invention whereinliquefaction and saccharification are combined, the viscosity of thelignocellulosic material in the one or more first containers is keptbetween 10 and 1000 cP, between 10 and 900 cP, between 10 and 800 cP,between 10 and 700 cP, between 10 and 600 cP, between 10 and 500 cP,between 10 and 400 cP, between 10 and 300 cP, between 10 and 200 cP andpreferably between 10 and 100 cP and/or the viscosity of thelignocellulosic material in the one or more second containers is keptbetween 10 and 1000 cP, between 10 and 900 cP, between 10 and 800 cP,between 10 and 700 cP, between 10 and 600 cP, between 10 and 500 cP,between 10 and 400 cP, between 10 and 300 cP, between 10 and 200 cP andpreferably between 10 and 100 cP.

In case of the process according to the present invention whereinliquefaction and saccharification are separate steps, the viscosity ofthe lignocellulosic material in the one or more first containers is keptbetween 10 and 1000 cP, between 10 and 900 cP, between 10 and 800 cP,between 10 and 700 cP, between 10 and 600 cP, between 10 and 500 cP,between 10 and 400 cP, between 10 and 300 cP, between 10 and 200 cP andpreferably between 10 and 100 cP and/or the viscosity of thelignocellulosic material in the one or more second containers is keptbetween 10 and 1000 cP, between 10 and 900 cP, between 10 and 800 cP,between 10 and 700 cP, between 10 and 600 cP, between 10 and 500 cP,between 10 and 400 cP, between 10 and 300 cP, between 10 and 200 cP andpreferably between 10 and 100 cP and/or the viscosity of thelignocellulosic material in the one or more third containers is keptbetween 10 and 1000 cP, between 10 and 900 cP, between 10 and 800 cP,between 10 and 700 cP, between 10 and 600 cP, between 10 and 500 cP,between 10 and 400 cP, between 10 and 300 cP, between 10 and 200 cP andpreferably between 10 and 100 cP.

The viscosity can be determined with a Brookfield DV III Rheometer atthe temperature used for the hydrolysis.

In an embodiment oxygen is added during at least part of the secondstage. Oxygen can be added continuously or discontinuously during thesecond stage. In an embodiment oxygen is added once or more than onceduring the second stage. In an embodiment oxygen may be added beforehydrolysis of the second stage, during a part of hydrolysis of thesecond stage, during the whole hydrolysis of the second stage or anycombination thereof. Oxygen is added to the one or more containers usedin the second stage.

Oxygen can be added in several forms. For example, oxygen can be addedas oxygen gas, oxygen-enriched gas, such as oxygen-enriched air, or air.Oxygen may also be added by means of in situ oxygen generation. Forexample, oxygen may be generated by electrolysis, oxygen may be producedenzymatically, e.g. by the addition of peroxide, or oxygen may beproduced chemically, e.g. by an oxygen generating system such as KHSO₅.For example, oxygen is produced from peroxide by catalase. The peroxidecan be added in the form of dissolved peroxide or generated by anenzymatic or chemical reaction. In case catalase is used as enzyme toproduce oxygen, catalase present in the enzyme composition for thehydrolysis can be used or catalase can be added for this purpose.

Examples how to add oxygen include, but are not limited to, addition ofoxygen by means of sparging, electrolysis, chemical addition of oxygen,filling the one or more containers used in the second stage and/or theone or more containers used for fermentation and/or the one or morecontainers used for propagation of the fermenting microorganisms fromthe top (plunging the hydrolysate into the tank and consequentlyintroducing oxygen into the hydrolysate) and addition of oxygen to theheadspace of said one or more containers. When oxygen is added to theheadspace of the container(s), sufficient oxygen necessary for thehydrolysis reaction may be supplied. In general, the amount of oxygenadded to the container(s) can be controlled and/or varied. Restrictionof the oxygen supplied is possible by adding only oxygen during part ofthe hydrolysis time in said container(s). Another option is addingoxygen at a low concentration, for example by using an mixture of airand recycled air (air leaving the container) or by “diluting” air withan inert gas. Increasing the amount of oxygen added can be achieved byaddition of oxygen during longer periods of the hydrolysis time, byadding the oxygen at a higher concentration or by adding more air.Another way to control the oxygen concentration is to add an oxygenconsumer and/or an oxygen generator. Oxygen can be introduced, forexample blown, into the liquid hydrolysis container contents oflignocellulosic material. It can also be blown into the headspace of thecontainer.

In an embodiment oxygen is added to the one or more containers used inthe second stage before and/or during and/or after the addition of thelignocellulosic material to said one or more containers. The oxygen maybe introduced together with the lignocellulosic material that enters thehydrolysis container(s). The oxygen may be introduced into the materialstream that will enter the container(s) or with part of the container(s)contents that passes an external loop of the container(s).

In an embodiment, the oxygen concentration (DO) in the lignocellulosicmaterial present during the enzymatic hydrolysis of the second stage isat least 0.0023 mol/m³, preferably at least 0.023 mol/m³, morepreferably at least 0.046 mol/m³, even more preferably at least 0.115mol/m³, most preferably at least 0.17 mol/m³ and in particular at least0.23 mol/m³. 0.23 mol/m³ corresponds to 100% DO at 32° C. Temperatureand pressure will influence the DO.

The preferred and exemplary mol/m³ values given above relate to normalatmospheric pressure and a temperature of about 32° C. The skilledperson in the art will appreciate favourable DO values on basis of thepresent teachings.

In the enzymatic hydrolysis amorphous and crystalline polysaccharides orcellulose are hydrolysed to sugars such as glucose. Amorphouspolysaccharides are for example converted to oligosaccharides byendoglucanases and then the oligosaccharides can be converted bycellobiohydrolases and beta-glucosidases to glucose. The conversion ofthe crystalline polysaccharides may occur in parallel or sequential andcontinue even when most of the amorphous polysaccharides are hydrolysed.The addition of oxygen in combination with lytic polysaccharidemonooxygenases is beneficial during the hydrolysis of the crystallinepolysaccharides for example in the degradation of the polysaccharidesinto oligosaccharides. The crystalline glucan structure can be opened bylytic polysaccharide monooxygenases. This type of enzyme opens up thestructure by oxidizing the glycosidic bonds and making it accessible forthe other cellulolytic enzymes for further hydrolysing theoligosaccharides into glucose. The addition of oxygen is very useful,especially in the phase wherein crystalline polysaccharides areconverted by enzymes.

The processes of the present invention show advantages, especially onpilot plant and industrial scale. In an embodiment the containers usedin the processes of the present invention have a volume of at least 1m³. Preferably, the containers have a volume of at least 1 m³, at least2 m³, at least 3 m³, at least 4 m³, at least 5 m³, at least 6 m³, atleast 7 m³, at least 8 m³, at least 9 m³, at least 10 m³, at least 15m³, at least 20 m³, at least 25 m³, at least 30 m³, at least 35 m³, atleast 40 m³, at least 45 m³, at least 50 m³, at least 60 m³, at least 70m³, at least 75 m³, at least 80 m³, at least 90 m³, at least 100 m³, atleast 200 m³, at least 300 m³, at least 400 m³, at least 500 m³, atleast 600 m³, at least 700 m³, at least 800 m³, at least 900 m³, atleast 1000 m³, at least 1500 m³, at least 2000 m³, at least 2500 m³. Ingeneral, the container(s) will be smaller than 3000 m³ or 5000 m³. Thecontainers used in the processes of the present invention may have thesame volume, but also may have a different volume.

In an embodiment the enzyme composition used in the processes of thepresent invention is derived from a fungus or the enzyme compositionused in the processes of the present invention comprises a fungalenzyme. In an embodiment the enzyme composition is derived from afilamentous fungus or the enzyme composition comprises a filamentousfungal enzyme. “Filamentous fungi” include all filamentous forms of thesubdivision Eumycota and Oomycota (as defined by Hawksworth et al., In,Ainsworth and Bisby's Dictionary of The Fungi, 8th edition, 1995, CABInternational, University Press, Cambridge, UK). The filamentous fungiare characterized by a mycelial wall composed of chitin, cellulose,glucan, chitosan, mannan, and other complex polysaccharides. Vegetativegrowth is by hyphal elongation and carbon catabolism is obligatoryaerobic. Filamentous fungal strains include, but are not limited to,strains of Acremonium, Agaricus, Aspergillus, Aureobasidium, Beauvaria,Cephalosporium, Ceriporiopsis, Chaetomium paecilomyces, Chrysosporium,Claviceps, Cochiobolus, Coprinus, Cryptococcus, Cyathus, Emericella,Endothia, Endothia mucor, Filibasidium, Fusarium, Geosmithia,Gilocladium, Humicola, Magnaporthe, Mucor, Myceliophthora, Myrothecium,Neocallimastix, Neurospora, Paecilomyces, Penicillium, Piromyces,Panerochaete, Pleurotus, Podospora, Pyricularia, Rasamsonia, Rhizomucor,Rhizopus, Scylatidium, Schizophyllum, Stagonospora, Talaromyces,Thermoascus, Thermomyces, Thielavia, Tolypocladium, Trametes pleurotus,Trichoderma and Trichophyton.

Several strains of filamentous fungi are readily accessible to thepublic in a number of culture collections, such as the American TypeCulture Collection (ATCC), Deutsche Sammlung von Mikroorganismen andZellkulturen GmbH (DSM), Centraalbureau Voor Schimmelcultures (CBS), andAgricultural Research Service Patent Culture Collection, NorthernRegional Research Center (NRRL). Examples of such strains includeAspergillus niger CBS 513.88, Aspergillus oryzae ATCC 20423, IFO 4177,ATCC 1011, ATCC 9576, ATCC14488-14491, ATCC 11601, ATCC12892, P.chrysogenum CBS 455.95, Penicillium citrinum ATCC 38065, Penicilliumchrysogenum P2, Talaromyces emersonii CBS 393.64, Acremonium chrysogenumATCC 36225 or ATCC 48272, Trichoderma reesei ATCC 26921 or ATCC 56765 orATCC 26921, Aspergillus sojae ATCC11906, Chrysosporium lucknowense C1,Garg 27K, VKM F-3500-D, ATCC44006 and derivatives thereof.

The processes of the invention are advantageously applied in combinationwith enzyme compositions derived from a microorganism of the genusRasamsonia, or the enzyme composition comprises a Rasamsonia enzyme.

The enzymatic hydrolysis of the first stage is preferably done at 50-90°C. In this step thermostable cellulolytic enzymes are preferred. A“thermostable” enzyme as used herein means that the enzyme has atemperature optimum of 50° C. or higher, 60° C. or higher, 70° C. orhigher, 75° C. or higher, 80° C. or higher, 85° C. or higher. They mayfor example be isolated from thermophilic microorganisms or may bedesigned by the skilled person and artificially synthesized. In oneembodiment the polynucleotides may be isolated or obtained fromthermophilic or thermotolerant filamentous fungi or isolated fromnon-thermophilic or non-thermotolerant fungi, but are found to bethermostable.

By “thermophilic fungus” is meant a fungus that grows at a temperatureof 50° C. or higher. By “themotolerant” fungus is meant a fungus thatgrows at a temperature of 45° C. or higher, having a maximum near 50° C.

Suitable thermophilic or thermotolerant fungal cells may be a Humicola,Rhizomucor, Myceliophthora, Rasamsonia, Talaromyces, Thermomyces,Thermoascus or Thielavia cell, preferably a Rasamsonia cell. Preferredthermophilic or thermotolerant fungi are Humicola grisea var.thermoidea, Humicola lanuginosa, Myceliophthora thermophila, Papulasporathermophilia, Rasamsonia byssochlamydoides, Rasamsonia emersonii,Rasamsonia argillacea, Rasamsonia eburnean, Rasamsonia brevistipitata,Rasamsonia cylindrospora, Rhizomucor pusillus, Rhizomucor miehei,Talaromyces baciffisporus, Talaromyces leycettanus, Talaromycesthermophilus, Thermomyces lenuginosus, Thermoascus crustaceus,Thermoascus thermophilus Thermoascus aurantiacus and Thielaviaterrestris.

Thermophilic fungi are not restricted to a specific taxonomic order andoccur all over the fungal tree of life. Examples are Rhizomucor in theMucorales, Myceliophthora in Sordariales and Talaromyces, Thermomycesand Thermoascus in the Eurotiales (see Mouchacca, 1997). The majority ofTalaromyces species are mesophiles, but exceptions are species withinsections Emersonii and Thermophila. Section Emersonii includesTalaromyces emersonii, Talaromyces byssochlamydoides, Talaromycesbaciffisporus and Talaromyces leycettanus, all of which grow well at 40°C. Talaromyces baciffisporus is thermotolerant, Talaromyces leycettanusis thermotolerant to thermophilic, and Talaromyces emersonii andTalaromyces byssochlamydoides are truly thermophilic (see Stolk andSamson, 1972). The sole member of Talaromyces section Thermophila,Talaromyces thermophilus, grows rapidly at 50° C. (see Stolk and Samson,1972). The current classification of these thermophilic Talaromycesspecies is mainly based on phenotypic and physiological characters, suchas their ability to grow above 40° C., ascospore color, the structure ofascornatal covering and the formation of a certain type of anamorph.Stolk and Samson (1972) stated that the members of the section Emersoniihave anamorphs of either Paecilomyces (Talaromyces byssochlamydoides andTalaromyces leycettanus) or Penicillium cylindrosporum series(Talaromyces emersonii and Talaromyces baciffisporus). Later, Pitt(1979) transferred the species belonging to the Penicilliumcylindrosporum series to the genus Geosmithia, based on variouscharacters such as the formation of conidia from terminal pores insteadof on collula (necks), a character of Penicillium and Paecilomyces.Within the genus Geosmithia, only Geosmithia argillacea isthermotolerant, and Stolk et al. (1969) and Evans (1971) proposed aconnection with members of Talaromyces sect. Emersonii. The phylogeneticrelationship of the themophilic Talaromyces species within Talaromycesand the Trichocomaceae is unknown. (see J. Houbraken, Antonie vanLeeuwenhoek 2012 February; 101(2): 403-21).

Rasamsonia is a new genus comprising thermotolerant and thermophilicTalaromyces and Geosmithia species (J. Houbraken et al., vida supra).Based on phenotypic, physiological and molecular data, Houbraken et al.proposed to transfer the species Talaromyces emersonii, Talaromycesbyssochlamydoides, Talaromyces eburneus, Geosmithia argillacea andGeosmithia cylindrospora to Rasamsonia gen. nov. Preferred thermophilicfungi are Rasamsonia byssochlamydoides, Rasamsonia emersonii,Thermomyces lenuginosus, Talaromyces thermophilus, Thermoascuscrustaceus, Thermoascus thermophilus and Thermoascus aurantiacus, withRasamsonia emersonii being most preferred. Talaromyces emersonii,Penicillium geosmithia emersonii and Rasamsonia emersonii are usedinterchangeably herein.

Cellulolytic enzymes of Rasamsonia applied on pretreated lignocellulosicfeedstock show maximal conversion rates at temperature within the rangeof 50 to 70° C. The enzymes remain active under these circumstances for14 days and more without complete cessation of activity. By usingoptimal temperature conditions, a maximal amount of reducing sugars canbe released from lignocellulosic material (total hydrolysis) within theshortest possible hydrolysis time. In this way, 100% conversion ofcellulose in glucose can be achieved in less than 5 days. Thetheoretical maximum yield (Yps max in g product per gram glucose) of afermentation product can be derived from textbook biochemistry. Forethanol, 1 mole of glucose (180 g) yields according to normal glycolysisfermentation pathway in yeast 2 moles of ethanol (=2×46=92 g ethanol).The theoretical maximum yield of ethanol on glucose is therefore92/180=0.511 g ethanol/g glucose. For butanol (MW 74 g/mole) orisobutanol, the theoretical maximum yield is 1 mole of butanol per moleof glucose. So Yps max for (iso-)butanol=74/180=0.411 g (iso-)butanol/gglucose. For lactic acid the fermentation yield for homolacticfermentation is 2 moles of lactic acid (MW=90 g/mole) per mole ofglucose. According to this stoichiometry, the Yps max=1 g lactic acid/gglucose. For other fermentation products a similar calculation may bemade. The cost reduction achieved with applying cellulolytic enzymes ofRasamsonia are the result of an overall process time reduction.

Due to the high stability of the enzymes used in the processes of thepresent invention, it is possible to lower the enzyme dosage and extendthe use of the enzyme by prolonging the hydrolysis times. For example,0.175 mL enzyme/g lignocellulosic material dry matter results in releaseof approximately 90% of the theoretical maximum of reducing sugars frompretreated lignocellulosic material within 72 h. When using 0.075 mLenzyme/g lignocellulosic material dry matter, approximately 90%conversion of the theoretical maximum is achieved within 120 h. Theresults show that, because of the stability of the enzyme activity,lowering the enzyme dosage can be compensated by extending thehydrolysis time to obtain the same amount of reducing sugars. The costreduction achieved by using stable cellulolytic enzymes, such as thoseof Rasamsonia, results in lower enzyme dosages that nevertheless resultin similar hydrolysis conversion yields.

In a common process for converting lignocellulosic material intoethanol, process steps are preferably done under septic conditions tolower the operational costs. Contamination and growth of contaminatingmicroorganisms can therefore occur and result in undesirable sideeffects, such as lactic acid, formic acid and acetic acid production,yield losses of ethanol on substrate, production of toxins andextracellular polysaccharides. These effects may affect production costssignificantly. A high process temperature and/or a short process timelimits the risk on contamination during hydrolysis and fermentation.Thermostable enzymes, like those of Rasamsonia, are capable ofhydrolysing lignocellulosic material at temperatures of higher than 60°C. At these temperatures, the risk that a contaminating microorganismwill cause undesired side effects is little to almost zero.

During the fermentation step, in which ethanol is produced, temperaturesare typically between 30 to 38° C. and are preferably not raised becauseof production losses. By applying short fermentation process times, therisks and effects of contamination and/or growth of contaminants arereduced as much as possible. With stable enzymes, like those ofRasamsonia, a short fermentation time can be applied and thus risks ofcontamination and/or growth of contaminants are reduced as much aspossible. The cost reduction achieved with applying thermostablecellulolytic enzymes of Rasamsonia in this way, results in a lower riskof process failures due to contamination.

The first step after thermal pretreatment is to cool the pretreatedmaterial to temperatures wherein the enzymes have an optimal activity.On large scale, this is typically done by adding (cooled) water, which,besides decreasing the temperature, reduces the dry matter content. Byusing thermostable enzymes, like those of Rasamsonia, cost reduction canbe achieved, because (i) less cooling of the pretreated material isrequired since higher temperatures are allowed during hydrolysis, and(ii) less water is added, which increases the dry matter content duringhydrolysis and fermentation and thus increase the ethanol productioncapacity (amount produced per time unit per volume) of an ethanol plant.By using thermostable enzymes, like those of Rasamsonia, cost reductionmay also be achieved by using cooling water having a higher temperaturethan the water that is used in a process with non-thermostable enzyme.

At the end of the hydrolysis, enzyme activities appear to be low, sincelittle reducing sugars are released once almost all cellulose isconverted. The amount of enzymatic activity present, however, hasdecreased only a little, assumingly mainly due to absorption of theenzymes to the substrate. By applying solid-liquid separation afterhydrolysis, such as centrifugation, filtration, cantation,sedimentation, 60% or more (e.g. 70%) of the enzyme activity in solutioncan be recovered and re-used for hydrolysis of a new pretreatedlignocellulosic material during the next hydrolysis.

Moreover, after solid-liquid separation the enzyme in solution can beseparated from the solution containing reducing sugars and otherhydrolysis products from the enzymatic actions. This separation can bedone by techniques including, but not limited to, ultra- andmicrofiltration, centrifugation, cantation, sedimentation, with orwithout first adsorption of the enzyme to a carrier of any kind. Forexample, after hydrolysis of pretreated material with 0.175 mL/gmaterial dry matter enzyme load for 20 h, 50% of the theoretical maximumamount of reducing sugars is liberated and after the same hydrolysis for72 h, 90% of the theoretical maximum amount of reducing sugars isliberated. By centrifugation and ultrafiltration, 60-70% of the enzymeactivity was recovered in the retentate, while the filtrate containedmore than 80% of the liberated reducing sugars. By re-using theretentate, either as it is or after further purification and/orconcentration, enzyme dosage during the next hydrolysis step can bereduced with 60 to 70%. The cost reduction achieved by using stablecellulolytic enzymes, such as those of Rasamsonia, in this way is theconsequence of a lower enzyme dosage.

The process including enzyme recycling after hydrolysis, as describedabove, can be combined with recycling of the ethanol producingmicroorganism after fermentation and with the use of the reducing sugarscontaining filtrate as a substrate (purified and/or concentrated ordiluted) in enzyme production fermentation and as substrate for thecultivation of the ethanol producing microorganism.

The thermostability of enzymes, like those from Rasamsonia, causesremaining cellulolytic activity after hydrolysis, fermentation andvacuum distillation in the thin stillage. The total activity of theenzyme is reduced during the three successive process steps. The thinstillage obtained after vacuum distillation can thus be re-used as asource of enzyme for a newly startedhydrolysis-fermentation-distillation process cycle of pretreatedmaterial conversion into ethanol. The thin stillage can be used eitherin concentrated or (un)diluted form and/or purified and with or withoutadditional enzyme supplementation.

In an optimal process, an amount of enzyme is supplemented into the thinstillage, before its re-use in a new process cycle, equal to the amountof activity lost during the three successive process steps of theprevious process cycle. In this way over dosage of enzyme is avoided andthus most efficient use of enzyme is obtained. Moreover, by providinghigh enzyme dosage in the first process cycle, and supplementing enzymeequal to the amount of activity lost during the three successive processsteps in the following process cycles, highest possible hydrolysis ratescan be obtained in each process cycle resulting in short hydrolysistimes of less than 48 h in combination with most efficient use ofenzymes.

By applying mixing during hydrolysis, enzymes come more often in contactwith substrates, which results in a more efficient use of the catalyticactivity. This will result in a lower enzyme dosages and thus in lowercosts, unless the mixing has a negative effect on the enzymes. Stableenzymes, like the thermostable enzymes from Rasamsonia, are robust andcan resist circumstances of (locally) high shear and temperatures, whichis the case during intensive mixing of slurries. The use of them inmixed systems is therefore beneficial and will lead to dosage and thuscosts reduction.

An advantage of expression and production of the enzymes (for example atleast two, three or four different cellulases) in a suitablemicroorganism may be a high enzyme composition yield which can be usedin the processes of the present invention.

In the processes of the present invention enzyme compositions are used.Preferably, the compositions are stable. “Stable enzyme compositions” asused herein means that the enzyme compositions retain activity after 30hours of hydrolysis reaction time, preferably at least 10%, 20%, 30%,40%, 50%, 60%, 65%, 70%, 75%, 80% 85%, 90%, 95%, 96%, 97%, 98%, 99% or100% of its initial activity after 30 hours of hydrolysis reaction time.Preferably, the enzyme composition retains activity after 40, 50, 60,70, 80, 90 100, 150, 200, 250, 300, 350, 400, 450, 500 hours ofhydrolysis reaction time.

The enzyme composition may be prepared by fermentation of a suitablesubstrate with a suitable microorganism, e.g. Rasamsonia emersonii orAspergillus niger, wherein the enzyme composition is produced by themicroorganism. The microorganism may be altered to improve or to makethe composition. For example, the microorganism may be mutated byclassical strain improvement procedures or by recombinant DNAtechniques. Therefore, the microorganisms mentioned herein can be usedas such to produce the composition or may be altered to increase theproduction or to produce an altered composition which might includeheterologous enzymes, e.g. cellulases, thus enzymes that are notoriginally produced by that microorganism. Preferably, a fungus, morepreferably a filamentous fungus is used to produce the composition.Advantageously, a thermophilic or thermotolerant microorganism is used.Optionally, a substrate is used that induces the expression of theenzymes in the enzyme composition during the production of the enzymecomposition.

The enzyme composition is used to release sugars from lignocellulosicmaterial, that comprises polysaccharides. The major polysaccharides arecellulose (glucans), hemicelluloses (xylans, heteroxylans andxyloglucans). In addition, some hemicellulose may be present asglucomannans, for example in wood-derived lignocellulosic material. Theenzymatic hydrolysis of these polysaccharides to soluble sugars,including both monomers and multimers, for example glucose, cellobiose,xylose, arabinose, galactose, fructose, mannose, rhamnose, ribose,galacturonic acid, glucoronic acid and other hexoses and pentoses occursunder the action of different enzymes acting in concert. By sugarproduct is meant the enzymatic hydrolysis product of the lignocellulosicmaterial. The sugar product comprises soluble sugars, including bothmonomers and multimers. Preferably, it comprises glucose. Examples ofother sugars are cellobiose, xylose, arabinose, galactose, fructose,mannose, rhamnose, ribose, galacturonic acid, glucoronic acid and otherhexoses and pentoses. The sugar product may be used as such or may befurther processed for example recovered and/or purified.

In addition, pectins and other pectic substances such as arabinans maymake up considerably proportion of the dry mass of typically cell wallsfrom non-woody plant tissues (about a quarter to half of dry mass may bepectins).

Cellulose is a linear polysaccharide composed of glucose residues linkedby β-1,4 bonds. The linear nature of the cellulose fibers, as well asthe stoichiometry of the β-linked glucose (relative to α) generatesstructures more prone to inter strand hydrogen bonding than the highlybranched α-linked structures of starch. Thus, cellulose polymers aregenerally less soluble and form more tightly bound fibers than thefibers found in starch.

Enzymes that may be included in the stable enzyme composition used inthe invention are described in more detail below.

Lytic polysaccharide monooxygenases, endoglucanases (EG) andexo-cellobiohydrolases (CBH) catalyze the hydrolysis of insolublecellulose to products such as cellooligosaccharides (cellobiose as amain product), while β-glucosidases (BG) convert the oligosaccharides,mainly cellobiose and cellotriose, to glucose.

Hemicellulose is a complex polymer, and its composition often varieswidely from organism to organism and from one tissue type to another. Ingeneral, a main component of hemicellulose is β-1,4-linked xylose, afive carbon sugar. However, this xylose is often branched at 0 to 3and/or 0 to 2 atoms of xylose, and can be substituted with linkages toarabinose, galactose, mannose, glucuronic acid, galacturonic acid or byesterification to acetic acid (and esterification of ferulic acid toarabinose). Hemicellulose can also contain glucan, which is a generalterm for β-linked six carbon sugars (such as the β-(1,3)(1,4) glucansand heteroglucans mentioned previously) and additionally glucomannans(in which both glucose and mannose are present in the linear backbone,linked to each other by β-linkages).

Xylanases together with other accessory enzymes, for exampleα-L-arabinofuranosidases, feruloyl and acetylxylan esterases,glucuronidases, and β-xylosidases) catalyze the hydrolysis ofhemicellulose.

Pectic substances include pectins, arabinans, galactans andarabinogalactans. Pectins are the most complex polysaccharides in theplant cell wall. They are built up around a core chain of α(1,4)-linkedD-galacturonic acid units interspersed to some degree with L-rhamnose.In any one cell wall there are a number of structural units that fitthis description and it has generally been considered that in a singlepectic molecule, the core chains of different structural units arecontinuous with one another. The principal types of structural unit are:galacturonan (homogalacturonan), which may be substituted with methanolon the carboxyl group and acetate on O-2 and O3; rhamnogalacturonan I(RGI), in which galacturonic acid units alternate with rhamnose unitscarrying (1,4)-linked galactan and (1,5)-linked arabinan side-chains.The arabinan side-chains may be attached directly to rhamnose orindirectly through the galactan chains; xylogalacturonan, with singlexylosyl units on O-3 of galacturonic acid (closely associated with RGI);and rhamnogalacturonan II (RGII), a particularly complex minor unitcontaining unusual sugars, for example apiose. An RGII unit may containtwo apiosyl residues which, under suitable ionic conditions, canreversibly form esters with borate.

An enzyme composition for use in the processes of the current inventioncomprises preferably at least two activities, although typically acomposition will comprise more than two activities, for example, three,four, five, six, seven, eight, nine or even more activities. Typically,an enzyme composition for use in the processes of the current inventioncomprises at least two cellulases. The at least two cellulases maycontain the same or different activities. The enzyme composition for usein the processes of the current invention may also comprises at leastone enzyme other than a cellulase. Preferably, the at least one otherenzyme has an auxiliary enzyme activity, i.e. an additional activitywhich, either directly or indirectly leads to lignocellulosedegradation. Examples of such auxiliary activities are mentioned hereinand include, but are not limited to hemicellulases.

Thus, a composition for use in the processes of the current inventionmay comprise lytic polysaccharide monooxygenase activity, endoglucanaseactivity and/or cellobiohydrolase activity and/or beta-glucosidaseactivity. A composition for use in the invention may comprise more thanone enzyme activity per activity class. For example, a composition foruse in the invention may comprise two endoglucanase activities, forexample, endo-1,3(1,4)-β glucanase activity and endo-β-1,4-glucanaseactivity.

A composition for use in the processes of the current invention may bederived from a fungus, such as a filamentous fungus such as Rasamsonia,such as Rasamsonia emersonii. In an embodiment a core set of(lignocellulose degrading) enzyme activities may be derived fromRasamsonia emersonii. Rasamsonia emersonii can provide a highlyeffective set of activities as demonstrated herein for the hydrolysis oflignocellulosic material. If needed, the set of activities can besupplemented with additional enzyme activities from other sources. Suchadditional activities may be derived from classical sources and/orproduced by a genetically modified organisms.

The activities in a composition for use in the processes of the currentinvention may be thermostable. Herein, this means that the activity hasa temperature optimum of 60° C. or higher, 70° C. or higher, 75° C. orhigher, 80° C. or higher, 85° C. or higher. Activities in a compositionfor use in the processes of the current invention will typically nothave the same temperature optima, but preferably will, nevertheless, bethermostable.

In addition, enzyme activities in a composition for use in the processesof the current invention may be able to work at low pH. For the purposesof this invention, low pH indicates a pH of 5.5 or lower, 5 or lower,4.9 or lower, 4.8 or lower, 4.7 or lower, 4.6 or lower, 4.5 or lower,4.4 or lower, 4.3 or lower, 4.2 or lower, 4.1 or lower, 4.0 or lower 3.9or lower, 3.8 or lower, 3.7 or lower, 3.6 or lower, 3.5 or lower.

Activities in a composition for use in the processes of the currentinvention may be defined by a combination of any of the abovetemperature optima and pH values.

The enzyme composition for use in the processes of the current inventionmay comprise a cellulase and/or a hemicellulase and/or a pectinase froma source other than Rasamsonia.

For example, the enzyme composition for use in the processes of thecurrent invention may comprise a beta-glucosidase (BG) from Aspergillus,such as Aspergillus oryzae, such as the one disclosed in WO 02/095014 orthe fusion protein having beta-glucosidase activity disclosed in WO2008/057637, or Aspergillus fumigatus, such as the one disclosed as SEQID NO:2 in WO 2005/047499 or SEQ ID NO:5 in WO 2014/130812 or anAspergillus fumigatus beta-glucosidase variant, such as one disclosed inWO 2012/044915, such as one with the following substitutions: F100D,S283G, N456E, F512Y (using SEQ ID NO: 5 in WO 2014/130812 fornumbering), or Aspergillus aculeatus or Aspergillus kawachi. In anotherembodiment the beta-glucosidase is derived from Penicillium, such asPenicillium brasilianum disclosed as SEQ ID NO:2 in WO 2007/019442, orfrom Trichoderma, such as Trichoderma reesei, such as ones described inU.S. Pat. No. 6,022,725, U.S. Pat. No. 6,982,159, U.S. Pat. No.7,045,332, U.S. Pat. No. 7,005,289, US 2006/0258554 US 2004/0102619. Inan embodiment even a bacterial beta-glucosidase can be used.

For example, the enzyme composition for use in the processes of thecurrent invention may comprise an endoglucanase (EG) from Trichoderma,such as Trichoderma reesei; from Humicola, such as a strain of Humicolainsolens; from Aspergillus, such as Aspergillus aculeatus or Aspergilluskawachii; from Erwinia, such as Erwinia carotovara; from Fusarium, suchas Fusarium oxysporum; from Thielavia, such as Thielavia terrestris;and/or from Chrysosporium, such as a strain of Chrysosporiumlucknowense. In an embodiment even a bacterial endoglucanase can beused.

For example, the enzyme composition for use in the processes of thecurrent invention may comprise a cellobiohydrolase I from Aspergillus,such as Aspergillus fumigatus, such as the Cel7A CBH I disclosed in SEQID NO:6 in WO 2011/057140 or SEQ ID NO:6 in WO 2014/130812, or fromTrichoderma, such as Trichoderma reesei.

For example, the enzyme composition for use in the processes of thecurrent invention may comprise a cellobiohydrolase II from Aspergillus,such as Aspergillus fumigatus, such as the one in SEQ ID NO:7 in WO2014/130812 or from Trichoderma, such as Trichoderma reesei, or fromThielavia, such as Thielavia terrestris, such as cellobiohydrolase IICEL6A from Thielavia terrestris.

For example, the enzyme composition for use in the processes of thecurrent invention may comprise a GH61 polypeptide (a lyticpolysaccharide monooxygenase) from Thermoascus, such as Thermoascusaurantiacus, such as the one described in WO 2005/074656 as SEQ ID NO:2and SEQ ID NO:1 in WO2014/130812; or from Thielavia, such as Thielaviaterrestris, such as the one described in WO 2005/074647 as SEQ ID NO: 8or SEQ ID NO:4 in WO2014/130812; or from Aspergillus, such asAspergillus fumigatus, such as the one described in WO 2010/138754 asSEQ ID NO:2 or SEQ ID NO: 3 in WO2014/130812; or from Penicillium, suchas Penicillium emersonii, such as the one disclosed as SEQ ID NO:2 in WO2011/041397 or SEQ ID NO:2 in WO2014/130812.

An enzyme composition for use in the processes of the current inventionmay comprise one, two, three, four classes or more of cellulase, forexample one, two, three or four or all of a lytic polysaccharidemonooxygenas (LPMO), an endoglucanase (EG), one or twoexo-cellobiohydrolase (CBH) and a beta-glucosidase (BG). A compositionfor use in the processes of the current invention may comprise two ormore of any of these classes of cellulase.

An enzyme composition for use in the processes of the current inventionmay comprise one type of cellulase activity and/or hemicellulaseactivity and/or pectinase activity provided by a composition asdescribed herein and a second type of cellulase activity and/orhemicellulase activity and/or pectinase activity provided by anadditional cellulase/hemicellulase/pectinase.

As used herein, a cellulase is any polypeptide which is capable ofdegrading or modifying cellulose. A polypeptide which is capable ofdegrading cellulose is one which is capable of catalyzing the process ofbreaking down cellulose into smaller units, either partially, forexample into cellodextrins, or completely into glucose monomers. Acellulase according to the invention may give rise to a mixed populationof cellodextrins and glucose monomers. Such degradation will typicallytake place by way of a hydrolysis reaction.

Lytic polysaccharide monooxygenases (LPMO) are recently classified byCAZy in family AA9 (Auxiliary Activity Family 9) or family AA10(Auxiliary Activity Family 10). As mentioned above, lytic polysaccharidemonooxygenases are able to open a crystalline glucan structure. Lyticpolysaccharide monooxygenases may also affect cello-oligosaccharides.GH61 (glycoside hydrolase family 61 or sometimes referred to EGIV)proteins are (lytic) oxygen-dependent polysaccharide monooxygenases(PMO's/LPMO's) according to the latest literature (see Isaksen et al.,Journal of Biological Chemistry, vol. 289, no. 5, pp. 2632-2642). PMOand LPMO are used herein interchangeably. Often in literature theseproteins are mentioned to enhance the action of cellulases onlignocellulose substrates. GH61 was originally classified asendoglucanase based on measurement of very weak endo-1,4-β-d-glucanaseactivity in one family member. The term “GH61” as used herein, is to beunderstood as a family of enzymes, which share common conserved sequenceportions and folding to be classified in family 61 of thewell-established CAZy GH classification system(http://www.cazy.org/GH61.html). The glycoside hydrolase family 61 is amember of the family of glycoside hydrolases EC 3.2.1. GH61 are recentlynow reclassified by CAZy in family AA9 (Auxiliary Activity Family 9).GH61 is used herein as being part of the cellulases.

CBM33 (family 33 carbohydrate-binding module) is a lytic polysaccharidemonooxygenase (see Isaksen et al, Journal of Biological Chemistry, vol.289, no. 5, pp. 2632-2642), CAZy has recently reclassified CBM33 in AA10(Auxiliary Activity Family 10).

As used herein, a hemicellulase is any polypeptide which is capable ofdegrading or modifying hemicellulose. That is to say, a hemicellulasemay be capable of degrading or modifying one or more of xylan,glucuronoxylan, arabinoxylan, glucomannan and xyloglucan. A polypeptidewhich is capable of degrading a hemicellulose is one which is capable ofcatalyzing the process of breaking down the hemicellulose into smallerpolysaccharides, either partially, for example into oligosaccharides, orcompletely into sugar monomers, for example hexose or pentose sugarmonomers. A hemicellulase according to the invention may give rise to amixed population of oligosaccharides and sugar monomers. Suchdegradation will typically take place by way of a hydrolysis reaction.

As used herein, a pectinase is any polypeptide which is capable ofdegrading or modifying pectin. A polypeptide which is capable ofdegrading pectin is one which is capable of catalyzing the process ofbreaking down pectin into smaller units, either partially, for exampleinto oligosaccharides, or completely into sugar monomers. A pectinaseaccording to the invention may give rise to a mixed population ofoligosacchardies and sugar monomers. Such degradation will typicallytake place by way of a hydrolysis reaction.

Accordingly, an enzyme composition for use in the processes of thecurrent invention may comprise any cellulase, for example, a lyticpolysaccharide monooxygenase (e.g. GH61), a cellobiohydrolase, anendo-β-1,4-glucanase, a beta-glucosidaseor a β-(1,3)(1,4)-glucanase.

As used herein, a cellobiohydrolase (EC 3.2.1.91) is any polypeptidewhich is capable of catalyzing the hydrolysis of 1,4-β-D-glucosidiclinkages in cellulose or cellotetraose, releasing cellobiose from theends of the chains. This enzyme may also be referred to as cellulase1,4-β-cellobiosidase, 1,4-β-cellobiohydrolase, 1,4-β-D-glucancellobiohydrolase, avicelase, exo-1,4-β-D-glucanase,exocellobiohydrolase or exoglucanase.

As used herein, an endo-β-1,4-glucanase (EC 3.2.1.4) is any polypeptidewhich is capable of catalyzing the endohydrolysis of 1,4-β-D-glucosidiclinkages in cellulose, lichenin or cereal β-D-glucans. Such apolypeptide may also be capable of hydrolyzing 1,4-linkages inβ-D-glucans also containing 1,3-linkages. This enzyme may also bereferred to as cellulase, avicelase, β-1,4-endoglucan hydrolase,β-1,4-glucanase, carboxymethyl cellulase, celludextrinase,endo-1,4-β-D-glucanase, endo-1,4-β-D-glucanohydrolase,endo-1,4-β-glucanase or endoglucanase.

As used herein, a beta-glucosidase (EC 3.2.1.21) is any polypeptidewhich is capable of catalysing the hydrolysis of terminal, non-reducingβ-D-glucose residues with release of β-D-glucose. Such a polypeptide mayhave a wide specificity for β-D-glucosides and may also hydrolyze one ormore of the following: a β-D-galactoside, an α-L-arabinoside, aβ-D-xyloside or a β-D-fucoside. This enzyme may also be referred to asamygdalase, β-D-glucoside glucohydrolase, cellobiase or gentobiase.

As used herein, a β-(1,3)(1,4)-glucanase (EC 3.2.1.73) is anypolypeptide which is capable of catalysing the hydrolysis of1,4-β-D-glucosidic linkages in β-D-glucans containing 1,3- and1,4-bonds. Such a polypeptide may act on lichenin and cerealβ-D-glucans, but not on β-D-glucans containing only 1,3- or 1,4-bonds.This enzyme may also be referred to as licheninase, 1,3-1,4-β-D-glucan4-glucanohydrolase, β-glucanase, endo-β-1,3-1,4 glucanase, lichenase ormixed linkage β-glucanase. An alternative for this type of enzyme is EC3.2.1.6, which is described as endo-1,3(4)-beta-glucanase. This type ofenzyme hydrolyses 1,3- or 1,4-linkages in beta-D-glucanse when theglucose residue whose reducing group is involved in the linkage to behydrolysed is itself substituted at C-3. Alternative names includeendo-1,3-beta-glucanase, laminarinase, 1,3-(1,3;1,4)-beta-D-glucan 3 (4)glucanohydrolase. Substrates include laminarin, lichenin and cerealbeta-D-glucans.

A composition for use in the processes of the current invention maycomprise any hemicellulase, for example, an endoxylanase, aβ-xylosidase, a α-L-arabionofuranosidase, an α-D-glucuronidase, anacetyl xylan esterase, a feruloyl esterase, a coumaroyl esterase, anα-galactosidase, a β-galactosidase, a β-mannanase or a β-mannosidase.

As used herein, an endoxylanase (EC 3.2.1.8) is any polypeptide which iscapable of catalysing the endohydrolysis of 1,4-β-D-xylosidic linkagesin xylans. This enzyme may also be referred to as endo-1,4-β-xylanase or1,4-β-D-xylan xylanohydrolase. An alternative is EC 3.2.1.136, aglucuronoarabinoxylan endoxylanase, an enzyme that is able to hydrolyze1,4 xylosidic linkages in glucuronoarabinoxylans.

As used herein, a β-xylosidase (EC 3.2.1.37) is any polypeptide which iscapable of catalysing the hydrolysis of 1,4-β-D-xylans, to removesuccessive D-xylose residues from the non-reducing termini. Such enzymesmay also hydrolyze xylobiose. This enzyme may also be referred to asxylan 1,4-β-xylosidase, 1,4-β-D-xylan xylohydrolase,exo-1,4-β-xylosidase or xylobiase.

As used herein, an α-L-arabinofuranosidase (EC 3.2.1.55) is anypolypeptide which is capable of acting on α-L-arabinofuranosides,α-L-arabinans containing (1,2) and/or (1,3)- and/or (1,5)-linkages,arabinoxylans and arabinogalactans. This enzyme may also be referred toas α-N-arabinofuranosidase, arabinofuranosidase or arabinosidase.

As used herein, an α-D-glucuronidase (EC 3.2.1.139) is any polypeptidewhich is capable of catalysing a reaction of the following form:alpha-D-glucuronoside+H(2)O=an alcohol+D-glucuronate. This enzyme mayalso be referred to as alpha-glucuronidase or alpha-glucosiduronase.These enzymes may also hydrolyse 4-O-methylated glucoronic acid, whichcan also be present as a substituent in xylans. An alternative is EC3.2.1.131: xylan alpha-1,2-glucuronosidase, which catalyses thehydrolysis of alpha-1,2-(4-O-methyl)glucuronosyl links.

As used herein, an acetyl xylan esterase (EC 3.1.1.72) is anypolypeptide which is capable of catalysing the deacetylation of xylansand xylo-oligosaccharides. Such a polypeptide may catalyze thehydrolysis of acetyl groups from polymeric xylan, acetylated xylose,acetylated glucose, alpha-napthyl acetate or p-nitrophenyl acetate but,typically, not from triacetylglycerol. Such a polypeptide typically doesnot act on acetylated mannan or pectin.

As used herein, a feruloyl esterase (EC 3.1.1.73) is any polypeptidewhich is capable of catalysing a reaction of the form:feruloyl-saccharide+H₂O=ferulate+saccharide. The saccharide may be, forexample, an oligosaccharide or a polysaccharide. It may typicallycatalyse the hydrolysis of the 4-hydroxy-3-methoxycinnamoyl (feruloyl)group from an esterified sugar, which is usually arabinose in ‘natural’substrates. p-nitrophenol acetate and methyl ferulate are typicallypoorer substrates. This enzyme may also be referred to as cinnamoylester hydrolase, ferulic acid esterase or hydroxycinnamoyl esterase. Itmay also be referred to as a hemicellulase accessory enzyme, since itmay help xylanases and pectinases to break down plant cell wallhemicellulose and pectin.

As used herein, a coumaroyl esterase (EC 3.1.1.73) is any polypeptidewhich is capable of catalysing a reaction of the form:coumaroyl-saccharide+H(2)O=coumarate+saccharide. The saccharide may be,for example, an oligosaccharide or a polysaccharide. This enzyme mayalso be referred to as trans-4-coumaroyl esterase, trans-p-coumaroylesterase, p-coumaroyl esterase or p-coumaric acid esterase. This enzymealso falls within EC 3.1.1.73 so may also be referred to as a feruloylesterase.

As used herein, an α-galactosidase (EC 3.2.1.22) is any polypeptidewhich is capable of catalysing the hydrolysis of terminal, non-reducingα-D-galactose residues in α-D-galactosides, including galactoseoligosaccharides, galactomannans, galactans and arabinogalactans. Such apolypeptide may also be capable of hydrolyzing α-D-fucosides. Thisenzyme may also be referred to as melibiase.

As used herein, a β-galactosidase (EC 3.2.1.23) is any polypeptide whichis capable of catalysing the hydrolysis of terminal non-reducingβ-D-galactose residues in β-D-galactosides. Such a polypeptide may alsobe capable of hydrolyzing α-L-arabinosides. This enzyme may also bereferred to as exo-(1->4)-β-D-galactanase or lactase.

As used herein, a β-mannanase (EC 3.2.1.78) is any polypeptide which iscapable of catalysing the random hydrolysis of 1,4-β-D-mannosidiclinkages in mannans, galactomannans and glucomannans. This enzyme mayalso be referred to as mannan endo-1,4-β-mannosidase orendo-1,4-mannanase.

As used herein, a β-mannosidase (EC 3.2.1.25) is any polypeptide whichis capable of catalysing the hydrolysis of terminal, non-reducingβ-D-mannose residues in β-D-mannosides. This enzyme may also be referredto as mannanase or mannase.

A composition for use in the processes of the current invention maycomprise any pectinase, for example an endo polygalacturonase, a pectinmethyl esterase, an endo-galactanase, a beta galactosidase, a pectinacetyl esterase, an endo-pectin lyase, pectate lyase, alpharhamnosidase, an exo-galacturonase, an expolygalacturonate lyase, arhamnogalacturonan hydrolase, a rhamnogalacturonan lyase, arhamnogalacturonan acetyl esterase, a rhamnogalacturonangalacturonohydrolase, a xylogalacturonase.

As used herein, an endo-polygalacturonase (EC 3.2.1.15) is anypolypeptide which is capable of catalysing the random hydrolysis of1,4-α-D-galactosiduronic linkages in pectate and other galacturonans.This enzyme may also be referred to as polygalacturonase pectindepolymerase, pectinase, endopolygalacturonase, pectolase, pectinhydrolase, pectin polygalacturonase, poly-α-1,4-galacturonideglycanohydrolase, endogalacturonase; endo-D-galacturonase orpoly(1,4-α-D-galacturonide) glycanohydrolase.

As used herein, a pectin methyl esterase (EC 3.1.1.11) is any enzymewhich is capable of catalysing the reaction: pectin+n H₂O=nmethanol+pectate. The enzyme may also been known as pectinesterase,pectin demethoxylase, pectin methoxylase, pectin methylesterase,pectase, pectinoesterase or pectin pectylhydrolase.

As used herein, an endo-galactanase (EC 3.2.1.89) is any enzyme capableof catalysing the endohydrolysis of 1,4-β-D-galactosidic linkages inarabinogalactans. The enzyme may also be known as arabinogalactanendo-1,4-β-galactosidase, endo-1,4-β-galactanase, galactanase,arabinogalactanase or arabinogalactan 4-β-D-galactanohydrolase.

As used herein, a pectin acetyl esterase is defined herein as any enzymewhich has an acetyl esterase activity which catalyses the deacetylationof the acetyl groups at the hydroxyl groups of GalUA residues of pectin.

As used herein, an endo-pectin lyase (EC 4.2.2.10) is any enzyme capableof catalysing the eliminative cleavage of (1→4)-α-D-galacturonan methylester to give oligosaccharides with4-deoxy-6-O-methyl-α-D-galact-4-enuronosyl groups at their non-reducingends. The enzyme may also be known as pectin lyase, pectintrans-eliminase; endo-pectin lyase, polymethylgalacturonictranseliminase, pectin methyltranseliminase, pectolyase, PL, PNL or PMGLor (1→4)-6-O-methyl-α-D-galacturonan lyase.

As used herein, a pectate lyase (EC 4.2.2.2) is any enzyme capable ofcatalysing the eliminative cleavage of (1→4)-α-D-galacturonan to giveoligosaccharides with 4-deoxy-α-D-galact-4-enuronosyl groups at theirnon-reducing ends. The enzyme may also be known polygalacturonictranseliminase, pectic acid transeliminase, polygalacturonate lyase,endopectin methyltranseliminase, pectate transeliminase,endogalacturonate transeliminase, pectic acid lyase, pectic lyase,α-1,4-D-endopolygalacturonic acid lyase, PGA lyase, PPase-N,endo-α-1,4-polygalacturonic acid lyase, polygalacturonic acid lyase,pectin trans-eliminase, polygalacturonic acid trans-eliminase or(1→4)-α-D-galacturonan lyase.

As used herein, an alpha rhamnosidase (EC 3.2.1.40) is any polypeptidewhich is capable of catalysing the hydrolysis of terminal non-reducingα-L-rhamnose residues in α-L-rhamnosides or alternatively inrhamnogalacturonan. This enzyme may also be known as α-L-rhamnosidase T,α-L-rhamnosidase N or α-L-rhamnoside rhamnohydrolase.

As used herein, exo-galacturonase (EC 3.2.1.82) is any polypeptidecapable of hydrolysis of pectic acid from the non-reducing end,releasing digalacturonate. The enzyme may also be known asexo-poly-α-galacturonosidase, exopolygalacturonosidase orexopolygalacturanosidase.

As used herein, exo-galacturonase (EC 3.2.1.67) is any polypeptidecapable of catalysing:(1,4-α-D-galacturonide)_(n)+H₂O=(1,4-α-D-galacturonide)_(n-1)+D-galacturonate.The enzyme may also be known as galacturan 1,4-α-galacturonidase,exopolygalacturonase, poly(galacturonate) hydrolase,exo-D-galacturonase, exo-D-galacturonanase, exopoly-D-galacturonase orpoly(1,4-α-D-galacturonide) galacturonohydrolase.

As used herein, exopolygalacturonate lyase (EC 4.2.2.9) is anypolypeptide capable of catalysing eliminative cleavage of4-(4-deoxy-α-D-galact-4-enuronosyl)-D-galacturonate from the reducingend of pectate, i.e. de-esterified pectin. This enzyme may be known aspectate disaccharide-lyase, pectate exo-lyase, exopectic acidtranseliminase, exopectate lyase, exopolygalacturonicacid-trans-eliminase, PATE, exo-PATE, exo-PGL or (1→4)-α-D-galacturonanreducing-end-disaccharide-lyase.

As used herein, rhamnogalacturonan hydrolase is any polypeptide which iscapable of hydrolyzing the linkage between galactosyluronic acid andrhamnopyranosyl in an endo-fashion in strictly alternatingrhamnogalacturonan structures, consisting of the disaccharide[(1,2-alpha-L-rhamnoyl-(1,4)-alpha-galactosyluronic acid].

As used herein, rhamnogalacturonan lyase is any polypeptide which is anypolypeptide which is capable of cleaving α-L-Rhap-(1→4)-α-D-GalpAlinkages in an endo-fashion in rhamnogalacturonan by beta-elimination.

As used herein, rhamnogalacturonan acetyl esterase is any polypeptidewhich catalyzes the deacetylation of the backbone of alternatingrhamnose and galacturonic acid residues in rhamnogalacturonan.

As used herein, rhamnogalacturonan galacturonohydrolase is anypolypeptide which is capable of hydrolyzing galacturonic acid from thenon-reducing end of strictly alternating rhamnogalacturonan structuresin an exo-fashion.

As used herein, xylogalacturonase is any polypeptide which acts onxylogalacturonan by cleaving the β-xylose substituted galacturonic acidbackbone in an endo-manner. This enzyme may also be known asxylogalacturonan hydrolase.

As used herein, an α-L-arabinofuranosidase (EC 3.2.1.55) is anypolypeptide which is capable of acting on α-L-arabinofuranosides,α-L-arabinans containing (1,2) and/or (1,3)- and/or (1,5)-linkages,arabinoxylans and arabinogalactans. This enzyme may also be referred toas α-N-arabinofuranosidase, arabinofuranosidase or arabinosidase.

As used herein, endo-arabinanase (EC 3.2.1.99) is any polypeptide whichis capable of catalysing endohydrolysis of 1,5-α-arabinofuranosidiclinkages in 1,5-arabinans. The enzyme may also be known asendo-arabinase, arabinan endo-1,5-α-L-arabinosidase,endo-1,5-α-L-arabinanase, endo-α-1,5-arabanase; endo-arabanase or1,5-α-L-arabinan 1,5-α-L-arabinanohydrolase.

An enzyme composition for use in the processes of the current inventionwill typically comprise at least two cellulases and optionally at leastone hemicellulase and optionally at least one pectinase. A compositionfor use in the processes of the current invention may comprise a lyticpolysaccharide monooxygenases (such as GH61), a cellobiohydrolase, anendoglucanase and/or a beta-glucosidase. Such a composition may alsocomprise one or more hemicellulases and/or one or more pectinases.

In addition, one or more (for example two, three, four or all) of anamylase, a protease, a lipase, a ligninase, a hexosyltransferase, aglucuronidase, an expansin, a cellulose induced protein or a celluloseintegrating protein or like protein may be present in a composition foruse in the processes of the current invention (these are referred to asauxiliary activities above).

“Protease” includes enzymes that hydrolyze peptide bonds (peptidases),as well as enzymes that hydrolyze bonds between peptides and othermoieties, such as sugars (glycopeptidases). Many proteases arecharacterized under EC 3.4 and are suitable for use in the processes ofthe current invention. Some specific types of proteases include,cysteine proteases including pepsin, papain and serine proteasesincluding chymotrypsins, carboxypeptidases and metalloendopeptidases.

“Lipase” includes enzymes that hydrolyze lipids, fatty acids, andacylglycerides, including phospoglycerides, lipoproteins,diacylglycerols, and the like. In plants, lipids are used as structuralcomponents to limit water loss and pathogen infection. These lipidsinclude waxes derived from fatty acids, as well as cutin and suberin.

“Ligninase” includes enzymes that can hydrolyze or break down thestructure of lignin polymers. Enzymes that can break down lignin includelignin peroxidases, manganese peroxidases, laccases and feruloylesterases, and other enzymes described in the art known to depolymerizeor otherwise break lignin polymers. Also included are enzymes capable ofhydrolyzing bonds formed between hemicellulosic sugars (notablyarabinose) and lignin. Ligninases include but are not limited to thefollowing group of enzymes: lignin peroxidases (EC 1.11.1.14), manganeseperoxidases (EC 1.11.1.13), laccases (EC 1.10.3.2) and feruloylesterases (EC 3.1.1.73).

“Hexosyltransferase” (2.4.1-) includes enzymes which are capable ofcatalysing a transferase reaction, but which can also catalyze ahydrolysis reaction, for example of cellulose and/or cellulosedegradation products. An example of a hexosyltransferase which may beused in the invention is a β-glucanosyltransferase. Such an enzyme maybe able to catalyze degradation of (1,3)(1,4)glucan and/or celluloseand/or a cellulose degradation product.

“Glucuronidase” includes enzymes that catalyze the hydrolysis of aglucoronoside, for example β-glucuronoside to yield an alcohol. Manyglucuronidases have been characterized and may be suitable for use inthe invention, for example β-glucuronidase (EC 3.2.1.31),hyalurono-glucuronidase (EC 3.2.1.36), glucuronosyl-disulfoglucosamineglucuronidase (3.2.1.56), glycyrrhizinate β-glucuronidase (3.2.1.128) orα-D-glucuronidase (EC 3.2.1.139).

A composition for use in the processes of the current invention maycomprise an expansin or expansin-like protein, such as a swollenin (seeSalheimo et al., Eur. J. Biochem. 269, 4202-4211, 2002) or aswollenin-like protein.

Expansins are implicated in loosening of the cell wall structure duringplant cell growth. Expansins have been proposed to disrupt hydrogenbonding between cellulose and other cell wall polysaccharides withouthaving hydrolytic activity. In this way, they are thought to allow thesliding of cellulose fibers and enlargement of the cell wall. Swollenin,an expansin-like protein contains an N-terminal Carbohydrate BindingModule Family 1 domain (CBD) and a C-terminal expansin-like domain. Forthe purposes of this invention, an expansin-like protein orswollenin-like protein may comprise one or both of such domains and/ormay disrupt the structure of cell walls (such as disrupting cellulosestructure), optionally without producing detectable amounts of reducingsugars.

A composition for use in the processes of the current invention maycomprise a cellulose induced protein, for example the polypeptideproduct of the cip1 or cip2 gene or similar genes (see Foreman et al.,J. Biol. Chem. 278(34), 31988-31997, 2003), a cellulose/cellulosomeintegrating protein, for example the polypeptide product of the cipA orcipC gene, or a scaffoldin or a scaffoldin-like protein. Scaffoldins andcellulose integrating proteins are multi-functional integrating subunitswhich may organize cellulolytic subunits into a multi-enzyme complex.This is accomplished by the interaction of two complementary classes ofdomain, i.e. a cohesion domain on scaffoldin and a dockerin domain oneach enzymatic unit. The scaffoldin subunit also bears acellulose-binding module (CBM) that mediates attachment of thecellulosome to its substrate. A scaffoldin or cellulose integratingprotein for the purposes of this invention may comprise one or both ofsuch domains.

A composition for use in the processes of the current invention may alsocomprise a catalase. The term “catalase” means a hydrogen-peroxide:hydrogen-peroxide oxidoreductase (EC 1.11.1.6 or EC 1.11.1.21) thatcatalyzes the conversion of two hydrogen peroxides to oxygen and twowaters. Catalase activity can be determined by monitoring thedegradation of hydrogen peroxide at 240 nm based on the followingreaction: 2H₂O₂→2H₂O+O₂. The reaction is conducted in 50 mM phosphate pH7.0 at 25° C. with 10.3 mM substrate (H₂O₂) and approximately 100 unitsof enzyme per ml. Absorbance is monitored spectrophotometrically within16-24 seconds, which should correspond to an absorbance reduction from0.45 to 0.4. One catalase activity unit can be expressed as onemicromole of H₂O₂ degraded per minute at pH 7.0 and 25° C.

A composition for use in the processes of the current invention may becomposed of a member of each of the classes of enzymes mentioned above,several members of one enzyme class, or any combination of these enzymesclasses or helper proteins (i.e. those proteins mentioned herein whichdo not have enzymatic activity per se, but do nevertheless assist inlignocellulosic degradation).

A composition for use in the processes of the current invention may becomposed of enzymes from (1) commercial suppliers; (2) cloned genesexpressing enzymes; (3) broth (such as that resulting from growth of amicrobial strain in media, wherein the strains secrete proteins andenzymes into the media; (4) cell lysates of strains grown as in (3);and/or (5) plant material expressing enzymes. Different enzymes in acomposition of the invention may be obtained from different sources.

The enzymes can be produced either exogenously in microorganisms,yeasts, fungi, bacteria or plants, then isolated and added, for example,to lignocellulosic material. Alternatively, the enzyme may be producedin a fermentation that uses (pretreated) lignocellulosic material (suchas corn stover or wheat straw) to provide nutrition to an organism thatproduces an enzyme(s). In this manner, plants that produce the enzymesmay themselves serve as a lignocellulosic material and be added intolignocellulosic material.

In the uses and methods described herein, the components of thecompositions described above may be provided concomitantly (i.e. as asingle composition per se) or separately or sequentially.

In an embodiment the enzyme compositions may be a whole fermentationbroth as described below. The whole fermentation broth can be preparedfrom fermentation of non-recombinant and/or recombinant filamentousfungi. In an embodiment the filamentous fungus is a recombinantfilamentous fungus comprising one or more genes which can be homologousor heterologous to the filamentous fungus. In an embodiment, thefilamentous fungus is a recombinant filamentous fungus comprising one ormore genes which can be homologous or heterologous to the filamentousfungus wherein the one or more genes encode enzymes that can degrade acellulosic substrate. The whole fermentation broth may comprise any ofthe polypeptides or any combination thereof.

Preferably, the enzyme composition is whole fermentation broth whereinthe cells are killed. The whole fermentation broth may contain organicacid(s) (used for killing the cells), killed cells and/or cell debris,and culture medium.

Generally, the filamentous fungi is cultivated in a cell culture mediumsuitable for production of enzymes capable of hydrolyzing a cellulosicsubstrate. The cultivation takes place in a suitable nutrient mediumcomprising carbon and nitrogen sources and inorganic salts, usingprocedures known in the art. Suitable culture media, temperature rangesand other conditions suitable for growth and cellulase and/orhemicellulase and/or pectinase production are known in the art. Thewhole fermentation broth can be prepared by growing the filamentousfungi to stationary phase and maintaining the filamentous fungi underlimiting carbon conditions for a period of time sufficient to expressthe one or more cellulases and/or hemicellulases and/or pectinases. Onceenzymes, such as cellulases and/or hemicellulases and/or pectinases, aresecreted by the filamentous fungi into the fermentation medium, thewhole fermentation broth can be used. The whole fermentation broth ofthe present invention may comprise filamentous fungi. In someembodiments, the whole fermentation broth comprises the unfractionatedcontents of the fermentation materials derived at the end of thefermentation. Typically, the whole fermentation broth comprises thespent culture medium and cell debris present after the filamentous fungiis grown to saturation, incubated under carbon-limiting conditions toallow protein synthesis (particularly, expression of cellulases and/orhemicellulases and/or pectinases). In some embodiments, the wholefermentation broth comprises the spent cell culture medium,extracellular enzymes and filamentous fungi. In some embodiments, thefilamentous fungi present in whole fermentation broth can be lysed,permeabilized, or killed using methods known in the art to produce acell-killed whole fermentation broth. In an embodiment, the wholefermentation broth is a cell-killed whole fermentation broth, whereinthe whole fermentation broth containing the filamentous fungi cells arelysed or killed. In some embodiments, the cells are killed by lysing thefilamentous fungi by chemical and/or pH treatment to generate thecell-killed whole broth of a fermentation of the filamentous fungi. Insome embodiments, the cells are killed by lysing the filamentous fungiby chemical and/or pH treatment and adjusting the pH of the cell-killedfermentation mix to a suitable pH. In an embodiment, the wholefermentation broth comprises a first organic acid component comprisingat least one 1-5 carbon organic acid and/or a salt thereof and a secondorganic acid component comprising at least 6 or more carbon organic acidand/or a salt thereof. In an embodiment, the first organic acidcomponent is acetic acid, formic acid, propionic acid, a salt thereof,or any combination thereof and the second organic acid component isbenzoic acid, cyclohexanecarboxylic acid, 4-methylvaleric acid,phenylacetic acid, a salt thereof, or any combination thereof.

The term “whole fermentation broth” as used herein refers to apreparation produced by cellular fermentation that undergoes no orminimal recovery and/or purification. For example, whole fermentationbroths are produced when microbial cultures are grown to saturation,incubated under carbon-limiting conditions to allow protein synthesis(e.g., expression of enzymes by host cells) and secretion into cellculture medium. Typically, the whole fermentation broth isunfractionated and comprises spent cell culture medium, extracellularenzymes, and microbial, preferably non-viable, cells.

If needed, the whole fermentation broth can be fractionated and the oneor more of the fractionated contents can be used. For instance, thekilled cells and/or cell debris can be removed from a whole fermentationbroth to provide a composition that is free of these components.

The whole fermentation broth may further comprise a preservative and/oranti-microbial agent. Such preservatives and/or agents are known in theart.

The whole fermentation broth as described herein is typically a liquid,but may contain insoluble components, such as killed cells, cell debris,culture media components, and/or insoluble enzyme(s). In someembodiments, insoluble components may be removed to provide a clarifiedwhole fermentation broth.

In an embodiment, the whole fermentation broth may be supplemented withone or more enzyme activities that are not expressed endogenously, orexpressed at relatively low level by the filamentous fungi, to improvethe degradation of the cellulosic substrate, for example, to fermentablesugars such as glucose or xylose. The supplemental enzyme(s) can beadded as a supplement to the whole fermentation broth and the enzymesmay be a component of a separate whole fermentation broth, or may bepurified, or minimally recovered and/or purified.

In an embodiment, the whole fermentation broth comprises a wholefermentation broth of a fermentation of a recombinant filamentous fungioverexpressing one or more enzymes to improve the degradation of thecellulosic substrate. Alternatively, the whole fermentation broth cancomprise a mixture of a whole fermentation broth of a fermentation of anon-recombinant filamentous fungus and a recombinant filamentous fungusoverexpressing one or more enzymes to improve the degradation of thecellulosic substrate. In an embodiment, the whole fermentation brothcomprises a whole fermentation broth of a fermentation of a filamentousfungi overexpressing beta-glucosidase. Alternatively, the wholefermentation broth for use in the present methods and reactivecompositions can comprise a mixture of a whole fermentation broth of afermentation of a non-recombinant filamentous fungus and a wholefermentation broth of a fermentation of a recombinant filamentous fungioverexpressing a beta-glucosidase.

As described above, an enzyme composition is present in the first stageand in the second stage of the processes of the current invention. Theseenzyme compositions may be the same or may be different. Furthermore, asdescribed above, additional enzymes are added during the first stageand/or the second stage of the processes according to the presentinvention. The enzymes added may be enzymes that are already present inthe first stage and in the second stage. Alternatively, they may bedifferent enzymes. Moreover, the additional enzymes added during thefirst stage may differ or may be the same as the additional enzymesadded during the second stage of the processes according to the presentinvention.

Lignocellulosic material as used herein includes any lignocellulosicand/or hemicellulosic material. Lignocellulosic material suitable foruse in the processes of the current invention includes biomass, e.g.virgin biomass and/or non-virgin biomass such as agricultural biomass,commercial organics, construction and demolition debris, municipal solidwaste, waste paper and yard waste. Common forms of biomass includetrees, shrubs and grasses, wheat, wheat straw, sugar cane, cane straw,sugar cane bagasse, switch grass, miscanthus, energy cane, corn, cornstover, corn husks, corn cobs, canola stems, soybean stems, sweetsorghum, corn kernel including fiber from kernels, products andby-products from milling of grains such as corn, wheat and barley(including wet milling and dry milling) often called “bran or fibre” aswell as municipal solid waste, waste paper and yard waste. The biomasscan also be, but is not limited to, herbaceous material, agriculturalresidues, forestry residues, municipal solid wastes, waste paper, andpulp and paper mill residues. “Agricultural biomass” includes branches,bushes, canes, corn and corn husks, energy crops, forests, fruits,flowers, grains, grasses, herbaceous crops, leaves, bark, needles, logs,roots, saplings, short rotation woody crops, shrubs, switch grasses,trees, vegetables, fruit peels, vines, sugar beet pulp, wheat midlings,oat hulls, and hard and soft woods (not including woods with deleteriousmaterials). In addition, agricultural biomass includes organic wastematerials generated from agricultural processes including farming andforestry activities, specifically including forestry wood waste.Agricultural biomass may be any of the aforementioned singularly or inany combination or mixture thereof.

Cellulose is an organic compound with the formula (C₆H₁₀O₅)_(n), apolysaccharide consisting of a linear chain of several hundred to overten thousand β(1→4) linked D-glucose units. A glucan molecule is apolysaccharide of D-glucose monomers linked by glycosidic bonds. Hereinglucan and cellulose are used interchangeably for a polysaccharide ofD-glucose monomers linked by glycosidic bonds. Methods for thequantitative analysis of glucan or polysaccharide compositions arewell-known and described in the art and are for example summarized inCarvalho de Souza et al., Carbohydrate Polymers 95 (2013) 657-663. Ingeneral, 50 to 70% of the glucan is crystalline cellulose, the remainderis amorphous cellulose.

In an embodiment the lignocellulosic material is pretreated beforeand/or during the enzymatic hydrolysis. Pretreatment methods are knownin the art and include, but are not limited to, heat, mechanical,chemical modification, biological modification and any combinationthereof. Pretreatment is typically performed in order to enhance theaccessibility of the lignocellulosic material to enzymatic hydrolysisand/or hydrolyse the hemicellulose and/or solubilize the hemicelluloseand/or cellulose and/or lignin, in the lignocellulosic material. In anembodiment, the pretreatment comprises treating the lignocellulosicmaterial with steam explosion, hot water treatment or treatment withdilute acid or dilute base. Examples of pretreatment methods include,but are not limited to, steam treatment (e.g. treatment at 100-260° C.,at a pressure of 7-45 bar, at neutral pH, for 1-10 minutes), dilute acidtreatment (e.g. treatment with 0.1-5% H₂SO₄ and/or SO₂ and/or HNO₃and/or HCl, in presence or absence of steam, at 120-200° C., at apressure of 2-15 bar, at acidic pH, for 2-30 minutes), organosolvtreatment (e.g. treatment with 1-1.5% H₂SO₄ in presence of organicsolvent and steam, at 160-200° C., at a pressure of 7-30 bar, at acidicpH, for 30-60 minutes), lime treatment (e.g. treatment with 0.1-2%NaOH/Ca(OH)₂in the presence of water/steam at 60-160° C., at a pressureof 1-10 bar, at alkaline pH, for 60-4800 minutes), ARP treatment (e.g.treatment with 5-15% NH₃, at 150-180° C., at a pressure of 9-17 bar, atalkaline pH, for 10-90 minutes), AFEX treatment (e.g. treatmentwith >15% NH₃, at 60-140° C., at a pressure of 8-20 bar, at alkaline pH,for 5-30 minutes).

The lignocellulosic material may be washed. In an embodiment thelignocellulosic material may be washed after the pretreatment. Thewashing step may be used to remove water soluble compounds that may actas inhibitors for the fermentation and/or hydrolysis step. The washingstep may be conducted in manner known to the skilled person. Next towashing, other detoxification methods do exist. The pretreatedlignocellulosic material may also be detoxified by any (or anycombination) of these methods which include, but are not limited to,solid/liquid separation, vacuum evaporation, extraction, adsorption,neutralization, overliming, addition of reducing agents, addition ofdetoxifying enzymes such as laccases or peroxidases, addition ofmicroorganisms capable of detoxification of hydrolysates.

The enzyme composition used in the process of the invention canextremely effectively hydrolyze lignocellulosic material, for examplecorn stover, wheat straw, cane straw, and/or sugar cane bagasse, whichcan then be further converted into a product, such as ethanol, biogas,butanol, a plastic, an organic acid, a solvent, an animal feedsupplement, a pharmaceutical, a vitamin, an amino acid, an enzyme or achemical feedstock. Additionally, intermediate products from a processfollowing the hydrolysis, for example lactic acid as intermediate inbiogas production, can be used as building block for other materials.The present invention is exemplified with the production of ethanol butthis is done as exemplification only rather than as limitation, theother products mentioned can be produced equally well.

In an embodiment the amount of enzyme composition added (herein alsocalled enzyme dosage or enzyme load) in the first stage is low. In anembodiment the amount of enzyme is 6 mg protein/g dry matter weight orlower, 5 mg protein/g dry matter or lower, 4 mg protein/g dry matter orlower, 3 mg protein/g dry matter or lower, 2 mg protein/g dry matter orlower, or 1 mg protein/g dry matter or lower (expressed as protein in mgprotein/g dry matter). In an embodiment, the amount of enzyme is 0.5 mgenzyme/g dry matter weight or lower, 0.4 mg enzyme composition/g drymatter weight or lower, 0.3 mg enzyme/g dry matter weight or lower, 0.25mg enzyme/g dry matter weight or lower, 0.20 mg enzyme/g dry matterweight or lower, 0.18 mg enzyme/g dry matter weight or lower, 0.15 mgenzyme/g dry matter weight or lower or 0.10 mg enzyme/g dry matterweight or lower (expressed as total of cellulase enzymes in mg enzyme/gdry matter). A low enzyme dosage is possible, because of the activityand stability of the enzymes. In case, also enzyme composition is addedin the second stage, the amount of enzyme composition added in theenzymatic hydrolysis in the first stage and/or the second stage maydiffer or may be the same.

The pH during the enzymatic hydrolysis of the first stage and/or thesecond stage may be chosen by the skilled person. In an embodiment thepH during the hydrolysis may be 3.0 to 6.4. The stable enzymes of theinvention may have a broad pH range of up to 2 pH units, up to 3 pHunits, up to 5 pH units. The optimum pH may lie within the limits of pH2.0 to 8.0, 2.5 to 7.5, 3.0 to 7.0, 3.5 to 6.5, 4.0 to 5.0, 4.0 to 4.5or is about 4.2. The pH used in the enzymatic hydrolysis of the firststage and the second stage may differ or may be the same. The optimum pHof the enzyme composition used in the enzymatic hydrolysis of the firststage and the second stage may differ or may be the same.

In an embodiment the hydrolysis step is conducted until 70% or more, 80%or more, 85% or more, 90% or more, 92% or more, 95% or more of availablesugar in the lignocellulosic material is released.

Significantly, a process of the invention may be carried out using highlevels of dry matter (of the lignocellulosic material) in the hydrolysisreaction. In an embodiment the dry matter content at the end of theenzymatic hydrolysis of the first stage is 5 wt % or higher, 6 wt % orhigher, 7 wt % or higher, 8 wt % or higher, 9 wt % or higher, 10 wt % orhigher, 11 wt % or higher, 12 wt % or higher, 13 wt % or higher, 14 wt %or higher, 15 wt % or higher, 16 wt % or higher, 17 wt % or higher, 18wt % or higher, 19 wt % or higher, 20 wt % or higher, 21 wt % or higher,22 wt % or higher, 23 wt % or higher, 24 wt % or higher, 25 wt % orhigher, 26 wt % or higher, 27 wt % or higher, 28 wt % or higher, 29 wt %or higher, 30 wt % or higher, 31 wt % or higher, 32 wt % or higher, 33wt % or higher, 34 wt % or higher, 35 wt % or higher, 36 wt % or higher,37 wt % or higher, 38 wt % or higher or 39 wt % or higher. In anembodiment the dry matter content at the end of the enzymatic hydrolysisof the first stage is between 5 wt %-40 wt %, 6 wt %-40 wt %, 7 wt %-40wt %, 8 wt %-40 wt %, 9 wt %-40 wt %, 10 wt %-40 wt %, 11 wt %-40 wt %,12 wt %-40 wt %, 13 wt %-40 wt %, 14 wt %-40 wt %, 15 wt %-40 wt %, 16wt %-40 wt %, 17 wt %-40 wt %, 18 wt %-40 wt %, 19 wt %-40 wt %, 20 wt%-40 wt %, 21 wt %-40 wt %, 22 wt %-40 wt %, 23 wt %-40 wt %, 24 wt %-40wt %, 25 wt %-40 wt %, 26 wt %-40 wt %, 27 wt %-40 wt %, 28 wt %-40 wt%, 29 wt %-40 wt %, 30 wt %-40 wt %, 31 wt %-40 wt %, 32 wt %-40 wt %,33 wt %-40 wt %, 34 wt %-40 wt %, 35 wt %-40 wt %, 36 wt %-40 wt %, 37wt %-40 wt %, 38 wt %-40 wt %, 39 wt %-40 wt %.

In an embodiment the dry matter content at the end of the enzymatichydrolysis of the second stage is 5 wt % or higher, 6 wt % or higher, 7wt % or higher, 8 wt % or higher, 9 wt % or higher, 10 wt % or higher,11 wt % or higher, 12 wt % or higher, 13 wt % or higher, 14 wt % orhigher, 15 wt % or higher, 16 wt % or higher, 17 wt % or higher, 18 wt %or higher, 19 wt % or higher, 20 wt % or higher, 21 wt % or higher, 22wt % or higher, 23 wt % or higher, 24 wt % or higher, 25 wt % or higher,26 wt % or higher, 27 wt % or higher, 28 wt % or higher, 29 wt % orhigher, 30 wt % or higher, 31 wt % or higher, 32 wt % or higher, 33 wt %or higher, 34 wt % or higher, 35 wt % or higher, 36 wt % or higher, 37wt % or higher, 38 wt % or higher or 39 wt % or higher. In an embodimentthe dry matter content at the end of the enzymatic hydrolysis of thesecond stage is between 5 wt %-40 wt %, 6 wt %-40 wt %, 7 wt %-40 wt %,8 wt %-40 wt %, 9 wt %-40 wt %, 10 wt %-40 wt %, 11 wt %-40 wt %, 12 wt%-40 wt %, 13 wt %-40 wt %, 14 wt %-40 wt %, 15 wt %-40 wt %, 16 wt %-40wt %, 17 wt %-40 wt %, 18 wt %-40 wt %, 19 wt %-40 wt %, 20 wt %-40 wt%, 21 wt %-40 wt %, 22 wt %-40 wt %, 23 wt %-40 wt %, 24 wt %-40 wt %,25 wt %-40 wt %, 26 wt %-40 wt %, 27 wt %-40 wt %, 28 wt %-40 wt %, 29wt %-40 wt %, 30 wt %-40 wt %, 31 wt %-40 wt %, 32 wt %-40 wt %, 33 wt%-40 wt %, 34 wt %-40 wt %, 35 wt %-40 wt %, 36 wt %-40 wt %, 37 wt %-40wt %, 38 wt %-40 wt %, 39 wt %-40 wt %.

In an embodiment the fermentation of the processes according to thepresent invention is performed in one or more containers. Thefermentation can be done in the same container(s) wherein the enzymatichydrolysis of the second stage is performed. Alternatively, thefermentation can be performed in one or more separate containers. In afurther aspect, the invention thus includes fermentation processes inwhich a microorganism is used for the fermentation of a carbon sourcecomprising sugar(s), e.g. glucose, L-arabinose and/or xylose. The carbonsource may include any carbohydrate oligo- or polymer comprisingL-arabinose, xylose or glucose units, such as e.g. lignocellulose,xylans, cellulose, starch, arabinan and the like. For release of xyloseor glucose units from such carbohydrates, appropriate carbohydrases(such as xylanases, glucanases, amylases and the like) may be added tothe fermentation medium or may be produced by the modified host cell. Inthe latter case, the modified host cell may be genetically engineered toproduce and excrete such carbohydrases. An additional advantage of usingoligo- or polymeric sources of glucose is that it enables to maintain alow(er) concentration of free glucose during the fermentation, e.g. byusing rate-limiting amounts of the carbohydrases. This, in turn, willprevent repression of systems required for metabolism and transport ofnon-glucose sugars such as xylose. In a preferred process the modifiedhost cell ferments both the L-arabinose (optionally xylose) and glucose,preferably simultaneously in which case preferably a modified host cellis used which is insensitive to glucose repression to prevent diauxicgrowth. In addition to a source of L-arabinose, optionally xylose (andglucose) as carbon source, the fermentation medium will further comprisethe appropriate ingredient required for growth of the modified hostcell. Compositions of fermentation media for growth of microorganismssuch as yeasts or filamentous fungi are well known in the art.

The fermentation time may be shorter than in conventional fermentationat the same conditions, wherein part of the enzymatic hydrolysis stillhas to take part during fermentation. In one embodiment, thefermentation time is 100 hours or less, 90 hours or less, 80 hours orless, 70 hours or less, or 60 hours or less, for a sugar composition of50 g/l glucose and corresponding other sugars from the lignocellulosicmaterial (e.g. 50 g/l xylose, 35 g/l L-arabinose and 10 g/l galactose).For more dilute sugar compositions, the fermentation time maycorrespondingly be reduced.

The fermentation process may be an aerobic or an anaerobic fermentationprocess. An anaerobic fermentation process is herein defined as afermentation process run in the absence of oxygen or in whichsubstantially no oxygen is consumed, preferably less than 5, 2.5 or 1mmol/L/h, more preferably 0 mmol/L/h is consumed (i.e. oxygenconsumption is not detectable), and wherein organic molecules serve asboth electron donor and electron acceptors. In the absence of oxygen,NADH produced in glycolysis and biomass formation, cannot be oxidised byoxidative phosphorylation. To solve this problem many microorganisms usepyruvate or one of its derivatives as an electron and hydrogen acceptorthereby regenerating NAD⁺. Thus, in a preferred anaerobic fermentationprocess pyruvate is used as an electron (and hydrogen acceptor) and isreduced to fermentation products such as ethanol, lactic acid,3-hydroxy-propionic acid, acrylic acid, acetic acid, succinic acid,citric acid, malic acid, fumaric acid, an amino acid, 1,3-propane-diol,ethylene, glycerol, butanol, a β-lactam antibiotics and a cephalosporin.In a preferred embodiment, the fermentation process is anaerobic. Ananaerobic process is advantageous, since it is cheaper than aerobicprocesses: less special equipment is needed. Furthermore, anaerobicprocesses are expected to give a higher product yield than aerobicprocesses. Under aerobic conditions, usually the biomass yield is higherthan under anaerobic conditions. As a consequence, usually under aerobicconditions, the expected product yield is lower than under anaerobicconditions.

In another embodiment, the fermentation process is under oxygen-limitedconditions. More preferably, the fermentation process is aerobic andunder oxygen-limited conditions. An oxygen-limited fermentation processis a process in which the oxygen consumption is limited by the oxygentransfer from the gas to the liquid. The degree of oxygen limitation isdetermined by the amount and composition of the ingoing gas flow as wellas the actual mixing/mass transfer properties of the fermentationequipment used. Preferably, in a process under oxygen-limitedconditions, the rate of oxygen consumption is at least 5.5, morepreferably at least 6 and even more preferably at least 7 mmol/L/h.

The fermentation process is preferably run at a temperature that isoptimal for the modified cell. Thus, for most yeasts or fungal cells,the fermentation process is performed at a temperature which is lessthan 42° C., preferably 38° C. or lower. For yeast or filamentous fungalhost cells, the fermentation process is preferably performed at atemperature which is lower than 35, 33, 30 or 28° C. and at atemperature which is higher than 20, 22, or 25° C.

In an embodiment of the invention, the fermentation is conducted with afermenting microorganism. In an embodiment the fermentation is performedin one or more containers. In an embodiment the second stage isperformed in the one or more fermentation containers. In an embodimentthe second stage is performed before the fermenting microorganism isadded to the one or more fermentation containers.

In an embodiment the second stage is performed together with thepropagation step of the fermenting microorganism. This means that thesecond stage is performed in one or more containers used for thepropagation of the fermenting microorgansims.

In an embodiment the fermenting microorganism is a microorganism that isable to ferment at least one C5 sugar. In an embodiment the process is aprocess for the production of ethanol, wherein the process comprises thestep of fermenting a medium containing sugar(s) with a microorganismthat is able to ferment at least one C5 sugar. The microorganism may bea prokaryotic or eukaryotic organism. The microorganism used in theprocess may be a genetically engineered microorganism. Examples ofsuitable organisms are yeasts, for instance Saccharomyces, e.g.Saccharomyces cerevisiae, Saccharomyces pastorianus or Saccharomycesuvarum, Hansenula, Issatchenkia, e.g. Issatchenkia orientalis, Pichia,e.g. Pichia stipites or Pichia pastoris, Kluyveromyces, e.g.Kluyveromyces fagilis, Candida, e.g. Candida pseudotropicalis or Candidaacidothermophilum, Pachysolen, e.g. Pachysolen tannophilus or bacteria,for instance Lactobacillus, e.g. Lactobacillus lactis, Geobacillus,Zymomonas, e.g. Zymomonas mobilis, Clostridium, e.g. Clostridiumphytofermentans, Escherichia, e.g. E. coli, Klebsiella, e.g. Klebsiellaoxytoca. In an embodiment the microorganism that is able to ferment atleast one C5 sugar is a yeast. In an embodiment, the yeast is belongs tothe genus Saccharomyces, preferably of the species Saccharomycescerevisiae. The yeast, e.g. Saccharomyces cerevisiae, used in theprocesses according to the present invention is capable of convertinghexose (C6) sugars and pentose (C5) sugars. The yeast, e.g.Saccharomyces cerevisiae, used in the processes according to the presentinvention can anaerobically ferment at least one C6 sugar and at leastone C5 sugar. For example, the yeast is capable of using L-arabinose andxylose in addition to glucose anaerobically. In an embodiment, the yeastis capable of converting L-arabinose into L-ribulose and/or xylulose5-phosphate and/or into a desired fermentation product, for example intoethanol. Organisms, for example Saccharomyces cerevisiae strains, ableto produce ethanol from L-arabinose may be produced by modifying a hostyeast introducing the araA (L-arabinose isomerase), araB(L-ribuloglyoxalate) and araD (L-ribulose-5-P4-epimerase) genes from asuitable source. Such genes may be introduced into a host cell in orderthat it is capable of using arabinose. Such an approach is given isdescribed in WO2003/095627. araA, araB and araD genes from Lactobacillusplantarum may be used and are disclosed in WO2008/041840. The araA genefrom Bacillus subtilis and the araB and araD genes from Escherichia colimay be used and are disclosed in EP1499708. In another embodiment, araA,araB and araD genes may derived from of at least one of the genusClavibacter, Arthrobacter and/or Gramella, in particular one ofClavibacter michiganensis, Arthrobacter aurescens, and/or Gramellaforsetii, as disclosed in WO 2009011591. In an embodiment, the yeast mayalso comprise one or more copies of xylose isomerase gene and/or one ormore copies of xylose reductase and/or xylitol dehydrogenase.

The yeast may comprise one or more genetic modifications to allow theyeast to ferment xylose. Examples of genetic modifications areintroduction of one or more xylA-gene, XYL1 gene and XYL2 gene and/orXKSI-gene; deletion of the aldose reductase (GRE3) gene; overexpressionof PPP-genes TAL1, TKL1, RPE1 and RKI1 to allow the increase of the fluxthrough the pentose phosphate pathway in the cell. Examples ofgenetically engineered yeast are described in EP1468093 and/orWO2006/009434.

An example of a suitable commercial yeast is RN1016 that is a xylose andglucose fermenting Saccharomyces cerevisiae strain from DSM, theNetherlands.

In an embodiment, the fermentation process for the production of ethanolis anaerobic. Anaerobic has already been defined earlier herein. Inanother preferred embodiment, the fermentation process for theproduction of ethanol is aerobic. In another preferred embodiment, thefermentation process for the production of ethanol is underoxygen-limited conditions, more preferably aerobic and underoxygen-limited conditions. Oxygen-limited conditions have already beendefined earlier herein.

The volumetric ethanol productivity is preferably at least 0.5, 1.0,1.5, 2.0, 2.5, 3.0, 5.0 or 10.0 g ethanol per litre per hour. Theethanol yield on L-arabinose and optionally xylose and/or glucose in theprocess preferably is at least 20, 25, 30, 35, 40, 45, 50, 60, 70, 80,90, 95 or 98%. The ethanol yield is herein defined as a percentage ofthe theoretical maximum yield, which, for glucose and L-arabinose andoptionally xylose is 0.51 g ethanol per g glucose or xylose.

In one aspect, the fermentation process leading to the production ofethanol, has several advantages by comparison to known ethanolfermentations processes: anaerobic processes are possible; oxygenlimited conditions are possible; higher ethanol yields and ethanolproduction rates can be obtained; the strain used may be able to useL-arabinose and optionally xylose.

Alternatively to the fermentation processes described above, at leasttwo distinct cells may be used, this means this process is aco-fermentation process. All preferred embodiments of the fermentationprocesses as described above are also preferred embodiments of thisco-fermentation process: identity of the fermentation product, identityof source of L-arabinose and source of xylose, conditions offermentation (aerobic or anaerobic conditions, oxygen-limitedconditions, temperature at which the process is being carried out,productivity of ethanol, yield of ethanol).

The fermentation process may be carried out without any requirement toadjust the pH during the process. That is to say, the process is onewhich may be carried out without the addition of any acid(s) or base(s).However, this excludes a pretreatment step, where acid may be added. Thepoint is that the enzyme composition used in the processes of theinvention is capable of acting at low pH and, therefore, there is noneed to adjust the pH of acid of an acid pretreated feedstock in orderthat hydrolysis may take place. Accordingly, the processes of theinvention may be zero waste processes using only organic products withno requirement for inorganic chemical input.

The overall reaction time (or the reaction time of hydrolysis step andfermentation step together) may be reduced. In one embodiment, theoverall reaction time is 300 hours or less, 200 hours or less, 150 hoursor less, 140 hours or less, 130 or less, 120 hours or less, 110 hours orless, 100 hours of less, 90 hours or less, 80 hours or less, 75 hours orless, or about 72 hours at 90% glucose yield. Correspondingly, loweroverall reaction times may be reached at lower glucose yield.

Fermentation products that may be produced by the processes of theinvention can be any substance derived from fermentation, They include,but are not limited to, alcohols (such as arabinitol, butanol, ethanol,glycerol, methanol, 1,3-propanediol, sorbitol, and xylitol); organicacid (such as acetic acid, acetonic acid, adipic acid, ascorbic acid,acrylic acid, citric acid, 2,5-diketo-D-gluconic acid, formic acid,fumaric acid, glucaric acid, gluconic acid, glucuronic acid, glutaricacid, 3-hydroxypropionic acid, itaconic acid, lactic acid, maleic acid,malic acid, malonic acid, oxalic acid, oxaloacetic acid, propionic acid,succinic acid, and xylonic acid); ketones (such as acetone); amino acids(such as aspartic acid, glutamic acid, glycine, lysine, serine,tryptophan, and threonine); alkanes (such as pentane, hexane, heptane,octane, nonane, decane, undecane, and dodecane), cycloalkanes (such ascyclopentane, cyclohexane, cycloheptane, and cyclooctane), alkenes (suchas pentene, hexene, heptene, and octene); and gases (such as methane,hydrogen (H₂), carbon dioxide (CO₂), and carbon monoxide (CO)). Thefermentation product can also be a protein, a vitamin, a pharmaceutical,an animal feed supplement, a specialty chemical, a chemical feedstock, aplastic, a solvent, ethylene, an enzyme, such as a protease, acellulase, an amylase, a glucanase, a lactase, a lipase, a lyase, anoxidoreductase, a transferase or a xylanase.

The processes according to the invention optionally comprise recovery offermentation product. A fermentation product may be separated from thefermentation broth in manner know to the skilled person. For eachfermentation product the skilled person will thus be able to select aproper separation technique. For instance, ethanol may be separated froma yeast fermentation broth by distillation, for instance steamdistillation/vacuum distillation in conventional way.

The beneficial effects of the present invention are found for severallignocellulosic materials and therefore believed to be present for thehydrolysis of all kind of lignocellulosic materials. This beneficialeffects of the present invention are found for several enzymecompositions and therefore believed to be present for all kind ofhydrolysing enzyme compositions.

EXAMPLES Example 1 The Effect of Oxygen Addition and Reduced Temperatureon Glucose Production and Ethanol Production

The following experiment is conducted to demonstrate the effect ofoxygen at reduced temperature during enzymatic hydrolysis. Two stirredtank reactors are filled with 1 kg of 20% w/w acid pretreated cornstover feedstock. The pH is adjusted to pH 4.5 using 10% w/w ammonia andthe temperature is set at 62° C. The obtained mixture is stirred at 60rpm using a marine impeller. 2.5 mg per gram of dry matter of acellulase enzyme cocktail comprising lytic polysaccharide monooxygenaseactivity (GH61 enzyme activity) is added to the mixture and the obtainedmixture is incubated for 120 hours.

The dissolved oxygen (DO) level is measured during the entire hydrolysisat 62° C. The DO level during the hydrolysis is constantly 0%,suggesting near anaerobic conditions. Gluconic acid formation ismeasured in hydrolysis samples. The amount of gluconic acid is 0.2 g/lin the supernatant of the hydrolysis samples taken from the mixtureduring the hydrolysis. Gluconic acid levels do not increase duringhydrolysis, suggesting no GH61 enzyme activity during hydrolysis.

Next, the temperature is decreased to 32° C. One reactor (experiment A)is further incubated for 24 hours at a stirring speed of 60 rpm. The DOin this reactor remains at 0% DO. The other reactor (experiment B) isincubated for 24 hours at a stirring speed of 250 rpm and a constantrefreshment of the head space in the reactor with fresh air at a flowrate of 100 ml/min. The DO in this reactor is about 100% during thisperiod. Gluconic acid analysis reveals that the gluconic acidconcentration increases in experiment B, while it remains constant inexperiment A. This suggests GH61 enzyme activity in experiment B and notin experiment A.

Next, the pH is adjusted to pH 5.5 using 10% w/w ammonia and 0.5 g/kghydrolysate of yeast is added to start the fermentation. Thefermentation is performed for 72 hours, while the pH is not controlledduring fermentation. The resulting glucose formation is shown in Table1.

Table 1 demonstrates a substantial increase in glucose production incase of a second stage enzymatic hydrolysis wherein the temperature islowered (to 32° C.) compared to the first stage hydrolysis and whereinaeration is applied during the second stage.

The amount of ethanol produced in experiment B (with aeration) is about20% higher compared to experiment A (without aeration).

Example 2 The Effect of Hydrolysis Time, Oxygen Addition and ReducedTemperature on Glucose Production and Ethanol Production

The following experiment is conducted to demonstrate the effect ofoxygen at reduced temperature during enzymatic hydrolysis. Two stirredtank reactors are filled with 1 kg of 20% w/w acid pretreated cornstover feedstock. The pH is adjusted to pH 4.5 using 10% w/w ammonia andthe temperature is set at 62° C. The reaction mixture is stirred at 60rpm using a marine impeller. 2.5 mg per gram of dry matter of acellulase enzyme cocktail comprising lytic polysaccharide monooxygenaseactivity (GH61 enzyme activity) is added to the mixture and the obtainedmixture is incubated for 120 hours in experiment A and 48 hours inexperiment B.

The dissolved oxygen (DO) level is measured during the entire hydrolysisat 62° C. The DO level during the hydrolysis is constantly 0%,suggesting near anaerobic conditions. Gluconic acid formation ismeasured in hydrolysis samples. The amount of gluconic acid is 0.2 g/lin the supernatant of the hydrolysis samples taken from the mixtureduring the hydrolysis. Gluconic acid levels do not increase duringhydrolysis, suggesting no GH61 enzyme activity during hydrolysis.

Next, the temperature is decreased to 32° C. Both reactors are furtherincubated for 24 hours at a stirring speed of 250 rpm and a constantrefreshment of the head space in the reactor with fresh air at a flowrate of 100 ml/min. The DO in the reactors is about 100% during thisperiod. Gluconic acid analysis reveals that the gluconic acidconcentration increases in both experiment, suggesting GH61 enzymeactivity in both experiments.

Next, the pH is adjusted to pH 5.5 using 10% w/w ammonia and 0.5 g/kghydrolysate of yeast is added to start the fermentation. Thefermentation is performed for 72 hours, while the pH is not controlledduring fermentation. The resulting glucose formation is shown in Table2.

Table 2 demonstrates for short and long hydrolysis times a substantialincrease in glucose production in case of a second stage enzymatichydrolysis wherein the temperature is lowered (to 32° C.) compared tothe first stage and wherein aeration is applied during the second stage.

The amount of ethanol produced in experiment A (long hydrolysis time) isthe same compared to experiment A (short hydrolysis time). This suggeststhat the experiment having the short hydrolysis time catches up duringfermentation which suggests additional monosaccharide formation duringfermentation.

Example 3 Less Enzyme Inactivation of Lower Hydrolysis Temperature

The effect of hydrolysis temperature on enzyme inactivation during thehydrolysis of a 20 wt % dry matter high acid pretreated corn stoverfeedstock by a cellulase mixture (2.7 mg/g dry matter) was evaluated.For this purpose, hydrolysis experiments were performed at 54° C. and62° C. in two separate stirred tank reactors filled with a 1 kg of the20 wt % dry matter high acid pretreated corn stover feedstock. Theheadspace of the reactions was constantly flushed with a flow ofnitrogen gas of 100 ml/min. Both reactions were stirred at 100 rpm usinga marine impeller and the pH was controlled at pH 4.5 via the additionof a 10% w/w ammonia solution. After 7 hours and 120 hoursrepresentative hydrolysate samples (thus including insolubles) weretaken from both reactions. Subsequently, these samples were dilutedthousand-fold and beta-glucosidase activity was determined in a routineassay.

In this assay, 0.4 ml of the diluted hydrolysate sample was added to 0.4ml of a substrate solution containing 6 mM4-nitrophenyl-β-D-glucopyranoside in 100 mM sodium acetate buffer pH4.5. After an incubation of 15 minutes at 60° C., the reaction wasstopped via the addition of 0.8 ml of a 1M sodium carbonate solution andthe absorbance was determined at a wavelength of 405 nm. Thebetaglucosidase activity was calculated using the molar extinctioncoefficient of para-nitrophenol.

Table 3 lists the beta-glucosidase activity present at the end ofhydrolysis (t=120 hours) as percentage of the activity determined after7 hours of hydrolysis for both temperatures. After 7 hours ofhydrolysis, no significant difference in beta-glucosidase activity wasdetected between the hydrolysates operated at the two differenttemperatures. The data in Table 3 clearly show that there is much lessbeta-glucosidase inactivation in the low temperature hydrolysate. Thushydrolysis temperature plays an important role in the inactivation ofcellulase enzymes and at lower temperature, less inactivation isobserved.

Example 4 Oxygen Dependent Enzyme Inactivation is Less at LowerHydrolysis Temperature

In another experiment, the effect of oxygen on enzyme inactivationduring hydrolysis was evaluated. For this purpose, four hydrolysisexperiments were performed at two different temperatures (54° C. and 62°C.) and for both temperatures under aerobic and anaerobic conditions.The hydrolysis reactions were performed in four stirred tank reactorsfilled with 1 kg of a 20 wt % dry matter high acid pretreated cornstover feedstock using 2.7 mg/g dry matter of a cellulase mixture. Theheadspace of the anaerobic, oxygen-free reaction was constantly flushedwith a flow of nitrogen gas of 100 ml/min, whereas the other hydrolysateheadspace was continuously flushed with normal air containing oxygen(100 ml/min). All reactions were stirred at 100 rpm using a marineimpeller and the pH was controlled at pH 4.5 via the addition of a 10%w/w ammonia solution. After 7 hours and 120 hours representativehydrolysate samples (thus including insolubles) were taken from bothreactions. Subsequently, these samples were diluted thousand-fold andendoglucanase activity was determined in a routine assay. In this assay,0.2 ml of the diluted hydrolysate sample was added to 0.2 ml of asubstrate solution containing 2 wt % dry matter AZO-CM-cellulose(Megazyme) in 100 mM sodium acetate buffer pH 4.5. After an incubationof 10 minutes at 60° C., the reaction was stopped via the addition of 1ml of a stop solution. This stop solution was made by dissolving 40 g ofsodium acetate and 4 g of zinc acetate in 200 ml water pH 5 (adjustedwith HCl) and mixing this with 800 ml 95% ethanol. After stop solutionaddition, the samples were vigorously vortexed for 10 seconds andcentrifuged for 10 minutes at 1000×g. The supernatant was transferred toa cuvette and the absorbance at 590 nm was measured together with theblanks (same procedure only without enzyme addition) and used todetermine endoglucanase activity (in mAU/mg·sec).

Table 4 lists the endoglucanase activity present at the end ofhydrolysis (t=120 hours) as percentage of the activity determined after7 hours of hydrolysis for all four conditions. No significant differencein endoglucanase activity was detected between the 7 hour samples of thefour hydrolysates.

The data in Table 4 show that there is more endoglucanase inactivationin the aerobic hydrolysis samples, suggesting a relation between oxygenand enzyme inactivation. Furthermore the data show that thisoxygen-dependent inactivation (calculated as the delta (Δ) between theN₂ and O₂ hydrolysis reactions) is less at lower temperature.

Example 5 The Effect of Lowering the Temperature During AeratedEnzymatic Hydrolysis of Acid Pretreated Corn Stover

This example demonstrates the effect of lowering the temperature duringenzymatic hydrolysis of pretreated corn stover under aeration.

The hydrolysis reactions were performed with acid pretreated corn stoverat a final concentration of 17.1% dry matter (w/w). The acid pretreatedcorn stover was prepared via dilution of a concentrated acid pretreatedcorn stover solution with water. Subsequently, the pH was adjusted to pH4.5 with a 10% (w/w) NH₄OH solution. The enzymatic hydrolysis wasconducted for 120 hours in a stirred (250 rpm), pH-controlled andtemperature-controlled reactor with a working volume of 1 l. Thehydrolysis was performed with 3.75 mg TEC-210 cellulase enzyme cocktailper g of dry matter. The TEC-210 cellulase enzyme cocktail was producedaccording to the inoculation and fermentation procedures described in WO2011/000949.

The following experiments were conducted:

1. The enzymatic hydrolysis was conducted in two stages. A first stagewherein the enzymatic hydrolysis was conducted at a temperature 62° C.for the first 48 hours under nitrogen (to exclude oxygen from thereaction; dissolved oxygen in the reaction mixture was 0 during thefirst stage). This was followed by a second stage wherein the enzymatichydrolysis was conducted for a period of 72 hours at a temperature of48° C. under oxygen (fresh air was added at a refreshment speed 0.1 vvm;dissolved oxygen in the reaction mixture was 100% during the secondstage).2. The enzymatic hydrolysis was conducted in two stages. A first stagewherein the enzymatic hydrolysis was conducted at a temperature 62.0 forthe first 48 hours under nitrogen (to exclude oxygen from the reaction;dissolved oxygen in the reaction mixture was 0 during the first stage).This was followed by a second stage wherein the enzymatic hydrolysis wasconducted for a period of 72 hours at a temperature of 62.0 under oxygen(fresh air was added at a refreshment speed 0.1 vvm; dissolved oxygen inthe reaction mixture was 100% during the second stage).

At the end of the hydrolysis samples were taken, cooled on ice,centrifuged and immediately 50 μl of each supernatant was diluted with1450 μl water. The diluted supernatant was subsequently filtered (0.45μm filter, Pall PN 454) and the filtrates were analysed for sugarcontent as described below.

The sugar concentrations of the diluted samples were measured using anHPLC equipped with an Aminex HPX-87P column (Biorad #1250098) by elutionwith water at 85° C. at a flow rate of 0.6 ml per minute and quantifiedby integration of the glucose signals from refractive index detection(R.I.) calibrated with glucose standard solutions.

The results are presented in Table 5. The results clearly show that moreglucose is formed in case the enzymatic hydrolysis is conducted in twostages and in the second stage the enzymatic hydrolysis is performedunder aeration and at a temperature that is lower than the temperatureof the first stage of the enzymatic hydrolysis compared to when theenzymatic hydrolysis is conducted in two stages and in the second stagethe enzymatic hydrolysis is performed under aeration and at atemperature that is not lower than the temperature of the first stage ofthe enzymatic hydrolysis.

TABLE 1 Glucose formation in presence and absence of aeration at highand low temperature. Glucose formation Experiment (g/l) A (withoutaeration at low T) At end of 62° C. period 48 At end of 32° C. period 50B (with aeration at low T) At end of 62° C. period 48 At end of 32° C.period 62

TABLE 2 Glucose formation in presence of aeration at low temperatureduring various hydrolysis times. Glucose formation Experiment (g/l) A(120 h hydrolysis at 62° C. + 24 h At end of 62° C. period 48 hydrolysisat 32° C. and aeration) At end of 32° C. period 62 B (48 h hydrolysis at62° C. + 24 h At end of 62° C. period 38 hydrolysis at 32° C. andaeration) At end of 32° C. period 53

TABLE 3 Relative beta-glucosidase activity in hydrolysate samples.Hydrolysis temperature 7 hr sample 120 hr sample 54° C. 100% 69% 62° C.100% 33%

TABLE 4 Relative endoglucanase activity in four hydrolysate samples.Hydrolysis condition 7 hr sample 120 hr sample Δ (N₂-O₂) 54° C. N₂ 100%82% 15% Air (O₂) 100% 67% 62° C. N₂ 100% 67% 40% Air (O₂) 100% 27%

TABLE 5 Glucose formation in a two-stage enzymatic hydrolysis process.Temperature Temperature during first during second stage of stage ofenzymatic enzymatic hydrolysis hydrolysis (absence of O₂; (presence ofO₂; Glucose* Experiment 48 hours) 72 hours) (in g/l) 1 62° C. 48° C.49.2 2 62° C. 62° C. 45.9 *glucose formation at the end of the enzymatichydrolysis

1. Process for preparation of a sugar product from lignocellulosicmaterial, comprising enzymatic hydrolysis of the lignocellulosicmaterial in one or more containers using an enzyme compositioncomprising at least two cellulases to obtain a sugar product, whereinthe enzymatic hydrolysis comprises at least: a first stage wherein theenzymatic hydrolysis is performed at a first temperature, and a secondstage wherein the enzymatic hydrolysis is performed at a secondtemperature, wherein the second temperature is lower than the firsttemperature and wherein oxygen is added to the hydrolysis during atleast part of the second stage.
 2. Process for the preparation of afermentation product from lignocellulosic material, comprising: a)performing a process according to claim 1, b) fermentation of the sugarproduct to produce a fermentation product; and c) optionally, recoveryof the fermentation product.
 3. Process according to claim 1, whereinthe first temperature is from 50-90° C.
 4. Process according to claim 1,wherein the second temperature is from 20-49° C.
 5. Process according toclaim 1, wherein the first stage takes 12-200 hours.
 6. Processaccording to claim 1, wherein the second stage takes 2-72 hours. 7.Process according to claim 1, wherein the first stage is performed inone or more first containers.
 8. Process according to claim 1, whereinthe second stage is performed in one or more second containers. 9.Process according to claim 8, wherein oxygen is added to the headspaceof the one or more second containers.
 10. Process according to claim 1,wherein the one or more first containers and/or one or more secondcontainers have a volume of at least 1 m³.
 11. Process according toclaim 1, wherein the enzyme composition is derived from a fungus and/orthe enzyme composition comprises a fungal enzyme.
 12. Process accordingto claim 2, wherein the fermentation is performed in one or morecontainers.
 13. Process according to claim 2, wherein the second stageis performed in the one or more fermentation containers.
 14. Processaccording to claim 2, wherein the second stage is performed in one ormore containers used for the propagation of fermenting microorganisms.15. Process according to claim 1, wherein the dry matter content at theend of the first stage is 5 wt % or higher.
 16. Process according toclaim 1, wherein the dry matter content at the end of the second stageis 5 wt % or higher.
 17. Process according to claim 1, wherein theenzyme composition is a whole fermentation broth.
 18. Process accordingto claim 2, wherein the fermentation is conducted with a microorganismthat is able to ferment at least one C5 sugar.
 19. Process according toclaim 1, wherein the lignocellulosic material is pretreated beforeand/or during the enzymatic hydrolysis.
 20. Process according to claim2, wherein the fermentation product is ethanol.